CN118473539A - Signal circuit, control method thereof and wearable device - Google Patents

Abstract

The present application relates to a signal circuit and a control method thereof, and a wearable device, and relates to the technical field of electronic equipment. It is used to solve the problem of low reliability of HBC signal transmission in an HBC communication system in which wearable devices participate. The signal circuit can be applied to a wearable device. The wearable device also includes a first electrode and a second electrode. The first electrode is used to send signals to human skin, and/or to receive signals transmitted by human skin. The signal circuit includes a first transceiver subcircuit and a compensation subcircuit. The first transceiver subcircuit includes a first signal terminal and a second signal terminal, the first signal terminal is used to couple with the first electrode; the second signal terminal is used to couple with the second electrode and the ground terminal at the same time. The compensation subcircuit includes a third signal terminal and a fourth signal terminal, the third signal terminal is used to couple with the first electrode, and the fourth signal terminal is used to couple with the second electrode.

Description

Signal circuit and control method thereof, and wearable device

Technical Field

The present disclosure relates to the technical field of electronic equipment, and in particular to a signal circuit and a control method thereof, and a wearable device.

Background Art

The battery capacity of wearable devices such as smart rings and smart watches is limited. To ensure battery life, extremely low-energy communication technologies are needed for communication. Human body communication (HBC), as an ultra-low-power communication technology for body area transmission, uses human tissue as a signal transmission channel. It has the characteristics of low channel loss and low communication power consumption. It is one of the feasible technical directions for future body area networks.

However, wearable devices are worn on the human body and have a variety of wearing scenarios. In some wearing scenarios, due to the contact or proximity of multiple parts of the human body with the wearable device, the signal will be greatly attenuated during the transmission process of the human body, reducing the reliability of HBC signal transmission in the HBC communication system in which the wearable device participates.

Summary of the invention

The embodiments of the present application provide a signal circuit and a control method thereof, and a wearable device, which are used to solve the problem of low HBC signal transmission reliability in an HBC communication system in which wearable devices participate.

To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

In a first aspect, a wearable device is provided. The wearable device includes a first electrode, a second electrode, an insulator, and a circuit board. The first electrode is used to couple with human skin. The second electrode is spaced apart from the first electrode. The insulator is located between the first electrode and the second electrode to insulate the first electrode and the second electrode from each other. The circuit board is located between the first electrode and the second electrode, the first connection point of the circuit board is coupled with the first electrode, and the second connection point of the circuit board is coupled with the second electrode. The wearable device uses at least the first electrode to send a signal to human skin, and/or receives a signal transmitted by human skin.

For ease of understanding, the following description will use a smart ring as a wearable device.

The inner surface of the first electrode may belong to the inner surface of the smart ring. The inner surface of the smart ring is the surface in contact with the finger wearing the smart ring, and the shape of the inner surface of the smart ring may be cylindrical. The inner surface of the first electrode may serve as part of the inner surface of the smart ring.

When the smart ring adopts capacitive coupling HBC, the first electrode can be used as a signal electrode. When the smart ring is used as a sending device of HBC signals, the signal electrode can send signals to human skin; when the smart ring is used as a receiving device of HBC signals, the signal electrode can receive signals transmitted by human skin.

The insulator may be located outside the first electrode. It is understandable that the insulator may be located on the side of the first electrode away from the finger wearing the smart ring. The insulator may cover the outer surface of the first electrode. Exemplarily, if the first electrode is entirely an arc structure, the insulator may cover the outer surface of the arc structure. Exemplarily, if part of the first electrode is an arc structure and the other part is a flat structure, the insulator may cover the outer surface of the arc structure and the outer surface of the flat structure.

The insulator may be an annular structure, and the inner ring surface of the insulator covers the outer surface of the first electrode.

In some examples, the insulator is provided with a recess, and the first electrode can be accommodated in the recess, so that the inner surface of the first electrode and the inner ring surface of the insulator form a continuous surface. In this way, the inner surface of the first electrode and the inner ring surface of the insulator can be used together as the inner surface of the smart ring. In addition, the problem of uncomfortable wearing of the smart ring caused by the step difference between the first electrode and the inner ring surface of the insulator can be avoided, thereby further improving the comfort of the user wearing the smart ring.

The second electrode is located on a side of the insulator away from the first electrode. In the case where the smart ring adopts capacitive coupling HBC, the second electrode can be used as a ground electrode.

In some examples, the second electrode may be a part of the housing of the smart ring. Exemplarily, the housing of the smart ring may include the first electrode and a plastic housing (or a housing made of other materials, which is only an example here, and the embodiments of the present application do not limit the housing material). The plastic housing and the first electrode are connected to each other, and the plastic housing may limit the position movement of the first electrode.

Exemplarily, the first electrode and the second electrode may include a metal material, such as at least one of copper, tungsten, silver, aluminum, etc. The embodiments of the present application do not limit the specific type of the metal material.

In some feasible implementations of the first aspect, the first electrode includes a first arcuate surface, and the second electrode includes a second arcuate surface, wherein a central angle of the second arcuate surface is greater than a central angle of the first arcuate surface.

The first electrode may be at least partially an arc-shaped structure, so that the inner surface of the first electrode may also be an arc-shaped surface, adapted to the shape of the finger wearing the smart ring, and in contact with the finger wearing the smart ring, so as to achieve coupling between the first electrode and human skin. Exemplarily, the first electrode may be partially an arc-shaped structure and partially a flat plate structure (or other structures, which are not limited in the embodiments of the present application); or, the first electrode may be entirely an arc-shaped structure.

The inner surface of the first electrode may be referred to as a first arcuate surface. The angle of the central angle of the first arcuate surface may be greater than 180°. The second electrode may be surrounded by a closed shape. The inner surface of the second electrode may be referred to as a second arcuate surface. The angle of the central angle of the second arcuate surface is 360°. The angle of the central angle of the second arcuate surface may be greater than the angle of the central angle of the first arcuate surface.

In some feasible implementations of the first aspect, the second electrode serves as a shell of the wearable device, and the shell has a receiving space. The insulator is at least partially located in the receiving space.

In some other examples, the second electrode can also be used as the entire housing of the smart ring. It can be understood that the second electrode forms a closed shape as the housing of the wearable device, and the first electrode and the insulator are located on the inner side of the second electrode. In this case, the housing is a full metal housing.

The housing of the smart ring has a storage space inside. The storage space is located between the inner contour of the second electrode and the outer contour of the second electrode. The insulator may be partially or completely located in the storage space. When the insulator is completely located in the storage space, the first electrode may be partially located in the storage space.

In this way, the insulator is at least partially located in the accommodation space of the second electrode, which can optimize the layout space of the smart ring, facilitate the miniaturized design of the smart ring, and improve the portability of the wearable device.

In some feasible implementations of the first aspect, the circuit board is located in the accommodating space, and the circuit board is located on a side of the insulator away from the first electrode. The wearable device also includes a conductive structure, one end of the conductive structure is coupled to the first connection point of the circuit board, and the other end of the conductive structure passes through the insulator and is coupled to the first electrode.

The circuit board is located on a side of the insulator away from the first electrode. It can be understood that the circuit board is located outside the insulator. The circuit board can be located in the accommodating space. Exemplarily, the circuit board can include a first circuit board segment, a second circuit board segment and a third circuit board segment, and the second circuit board segment and the third circuit board segment are respectively connected to opposite ends of the first circuit board segment. The extension direction of the first circuit board segment and the extension direction of the second circuit board segment intersect each other, and the extension direction of the first circuit board segment and the extension direction of the third circuit board segment intersect each other.

Exemplarily, the second circuit board segment and the third circuit board segment are symmetrically arranged along an axis perpendicular to the first circuit board segment.

In some examples, the same circuit board segment may be coupled to the first electrode and the second electrode. For example, the first circuit board segment is coupled to the first electrode and the second electrode at the same time. In other examples, different circuit board segments may be coupled to the first electrode and the second electrode respectively. For example, the first circuit board segment is coupled to the second electrode, and the third circuit board segment is coupled to the first electrode.

The circuit board can be coupled to the second electrode by directly contacting the second electrode through the conductive structure. The circuit board can be coupled to the first electrode by contacting the first electrode through the conductive structure through the insulator.

The above-mentioned conductive structure can be a metal spring, a conductive cloth, a conductive glue or a metal wire or other structure that can conduct electrical signals, and the embodiments of the present application are not limited to this.

In this way, by accommodating the circuit board in the accommodating space of the second electrode, it is beneficial to the miniaturized design of the smart ring. At the same time, the first electrode and the second electrode can be coupled to the circuit board through the conductive structure, thereby improving the reliability of the wearable device.

In some feasible implementations of the first aspect, the insulator includes a flexible material. For example, the flexible material may be a flexible insulating material such as rubber or foam, which is not limited in the embodiments of the present application. The insulator may be formed into a closed shape as a buffer layer between the finger wearing the smart ring and the housing of the smart ring, thereby improving the comfort of the user wearing the smart ring.

In some feasible implementations of the first aspect, the wearable device includes a finger ring or a ring.

In a second aspect, a signal circuit is provided. The signal circuit can be applied to a wearable device. The wearable device also includes a first electrode and a second electrode. The first electrode is used to send a signal to human skin and/or receive a signal transmitted by human skin. The signal circuit includes a first transceiver subcircuit and a compensation subcircuit. The first transceiver subcircuit includes a first signal terminal and a second signal terminal, the first signal terminal is used to couple with the first electrode; the second signal terminal is used to couple with the second electrode and the ground terminal at the same time. The compensation subcircuit includes a third signal terminal and a fourth signal terminal, the third signal terminal is used to couple with the first electrode, and the fourth signal terminal is used to couple with the second electrode.

The first transceiver subcircuit may be a signal transceiver subcircuit of a capacitive coupling type HBC. The first transceiver subcircuit may include a first signal terminal and a second signal terminal. The first signal terminal may be coupled to the first electrode, so that the first electrode serves as a signal electrode of the smart ring. The second signal terminal may be coupled to the second electrode and coupled to the ground terminal, so that the second electrode serves as a ground electrode of the smart ring.

The compensation subcircuit may include a third signal terminal and a fourth signal terminal. The third signal terminal may be coupled to the first electrode, and the fourth signal terminal may be coupled to the second electrode. It can be understood that the compensation subcircuit and the first transceiver subcircuit are connected in parallel.

When the second electrode is in contact with human skin (for example, a finger other than the finger wearing the smart ring), the contact between the second electrode and the human skin can be equivalent to forming a first capacitor. The capacitance value of the first capacitor formed equivalently can also be different depending on the degree of contact between the human skin and the second electrode.

It should be noted that the first capacitor does not belong to the signal circuit. The first capacitor is an electronic device that is equivalent to the contact between the second electrode and the human skin.

The first capacitor equivalently formed by the contact between the second electrode in the signal circuit and the human skin will increase the transmission loss of the human body channel, thereby resulting in low reliability of HBC signal transmission in the HBC communication system involving the signal circuit and the wearable device.

The compensation subcircuit is used to form a parallel resonant network together with the first capacitor. The parallel resonant network can be equivalent to an open circuit in the signal circuit, thereby disconnecting the first capacitor from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and the wearable device participate.

In some feasible implementations of the second aspect, when the second electrode is coupled to human skin, a first capacitor is equivalently formed between the second electrode and the human skin. The compensation subcircuit is used to form a parallel resonant network together with the first capacitor.

The parallel resonant network can be equivalent to an open circuit in the signal circuit, thereby disconnecting the first capacitor from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system involving the signal circuit and wearable devices.

In some feasible implementations of the second aspect, the compensation subcircuit includes a first inductor. A first end of the first inductor is used to couple with the first electrode, and a second end of the first inductor is used to couple with the second electrode. The first inductor includes a fixed value inductor or an adjustable inductor.

The first end of the first inductor is coupled to the first electrode, and the second end of the first inductor is coupled to the second electrode. The first inductor and the first capacitor are substantially equivalent to a parallel relationship, thereby forming a parallel LC (L represents the first inductor, C represents the first capacitor) resonant network.

The parallel LC resonant network can be equivalent to an open circuit in the signal circuit, thereby disconnecting the first capacitor from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system involving the signal circuit and wearable devices.

By selecting first inductors with different inductance values, the inductance parameters in the LC resonant network formed by the first capacitor and the first inductor being connected in parallel can be adjusted. Alternatively, the first inductor can be an adjustable inductor whose inductance value can be adjusted, and by adjusting the capacitance value of the first inductor, the inductance parameters in the LC resonant network formed by the first capacitor and the first inductor being connected in parallel can also be adjusted.

Exemplarily, the first inductor may include an active inductor. Of course, the first inductor may also use other inductor types or circuits to adjust the inductance value, which is not limited in the embodiments of the present application.

In some feasible implementations of the second aspect, the compensation subcircuit includes an inductor component. A first end of the inductor component is used to couple with the first electrode, and a second end of the inductor component is used to couple with the second electrode. The inductor component includes a plurality of inductor units connected in series. Each inductor unit includes a first switch and a second inductor connected in parallel.

Multiple second inductors are connected in series with each other. For example, the first end of the first second inductor among the multiple second inductors is coupled to the first electrode as the third signal end, the second end of the first second inductor is coupled to the first end of the second second inductor, the second end of the second second inductor is coupled to the first end of the third second inductor, and so on... until the second end of the last second inductor is coupled to the second electrode as the fourth signal end.

In addition, each second inductor may be connected in parallel with a first switch. The first end of the second inductor is coupled to the first end of the first switch, and the second end of the second inductor is coupled to the second end of the first switch. When the first switch is in a closed state, the first end of the first switch is connected to the second end of the first switch; when the first switch is in an open state, the first end of the first switch is disconnected from the second end of the first switch.

The multiple second inductors may be multiple inductors with equal inductance values, or may be multiple inductors with unequal inductance values, which is not limited in the embodiments of the present application.

In a set of mutually parallel selection units and second inductors, when the first switch in the selection unit is in an open state, the selection unit is in an open circuit state. In this way, the current passes through the second inductor, so that the second inductor is effective in the compensation subcircuit. When the first switch in the selection unit is in a closed state, the selection unit is in a pass state. In this way, the current does not pass through the second inductor but passes through the selection unit, so that the second inductor is not effective in the compensation subcircuit.

By switching the state of the first switch in each group of mutually parallel selection units and second inductors, it is possible to control whether the second inductor in the group of mutually parallel selection units and second inductors is effective, thereby controlling whether the multiple second inductors in the compensation subcircuit are effective. In other words, by controlling the states of the multiple first switches, the effective number of the multiple second inductors in the compensation subcircuit can be adjusted.

As described above, the plurality of second inductors are connected in series with each other. Therefore, by controlling the states of the plurality of first switches to control the effective number of the plurality of second inductors, the inductance value of the inductor assembly (i.e., the inductance value of the compensation subcircuit) can be adjusted. In this way, the compensation subcircuit and the first capacitor can form a parallel LC resonant network, and the parallel LC resonant network can reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and the wearable device participate.

In some feasible implementations of the second aspect, the compensation subcircuit further includes a second capacitor. The first plate of the second capacitor is used to couple with the first electrode, and the second plate of the second capacitor is used to couple with the second electrode. The second capacitor includes a fixed value capacitor or an adjustable capacitor.

Taking the compensation subcircuit including the second capacitor and the first inductor as an example, the second capacitor and the first inductor in the compensation subcircuit are connected in parallel with each other. As explained before, the first inductor is connected in parallel with the first capacitor, and here the second capacitor is connected in parallel with the first inductor, so the first capacitor and the second capacitor are connected in parallel.

By selecting a second capacitor with different capacitance values, the capacitance value of the first capacitor and the second capacitor connected in parallel can be adjusted. Alternatively, the second capacitor can be an adjustable capacitor whose capacitance value can be adjusted, and by adjusting the capacitance value of the second capacitor, the capacitance value of the first capacitor and the second capacitor connected in parallel can also be adjusted.

In this way, the compensation subcircuit can adjust the capacitance value in the parallel LC resonant circuit through the second capacitor, which can help the compensation subcircuit and the first capacitor to form a parallel LC resonant network, so that the parallel LC resonant network can reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and the wearable device participate.

In some feasible implementations of the second aspect, the compensation subcircuit further includes a capacitor assembly. The capacitor assembly includes a plurality of capacitor units connected in parallel. The first end of each capacitor unit is used to couple with the first electrode, and the second end of each capacitor unit is used to couple with the second electrode. Each capacitor unit includes a second switch and a third capacitor connected in series.

The first plate of each third capacitor is coupled to the first electrode, and the second plate of each third capacitor is coupled to the second electrode and the ground terminal. In addition, a second switch may be connected in series between each third capacitor and the first electrode. The first end of the second switch is coupled to the first electrode, and the second end of the second switch is coupled to the first plate of the third capacitor. Of course, the second switch may also be connected in series between the third capacitor and the ground terminal.

When the second switch is in a closed state, the first end of the second switch is connected to the second end of the second switch; when the second switch is in an open state, the first end of the second switch is disconnected from the second end of the second switch.

The multiple third capacitors may be multiple capacitors with equal capacitance values, or may be multiple capacitors with unequal capacitance values, which is not limited in the embodiments of the present application.

In a set of second switch and third capacitor connected in series, when the second switch is in an open state, the circuit between the third capacitor and the first electrode is in an open state. In this way, the current will not be conducted to the third capacitor, so that the third capacitor will not be effective in the compensation sub-circuit. When the second switch is in a closed state, the circuit between the third capacitor and the first electrode is in a conductive state. In this way, the current can be conducted to the third capacitor, so that the third capacitor will be effective in the compensation sub-circuit.

The effective plurality of third capacitors are connected in parallel with each other, so the capacitance value of the capacitor assembly can be calculated based on the capacitance values of the effective plurality of third capacitors.

By switching the state of the second switch in each group of second switches and third capacitors connected in series, it is possible to control whether the third capacitor in the group of second switches and third capacitors connected in series is effective, thereby controlling whether the multiple third capacitors in the compensation sub-circuit are effective. In other words, by controlling the states of the multiple second switches, it is possible to adjust the effective number of the multiple third capacitors in the capacitor assembly, thereby adjusting the capacitance value of the capacitor assembly.

The capacitor assembly is similar to the second capacitor and is also connected in parallel with the first capacitor. Therefore, by adjusting the capacitance value of the capacitor assembly, the capacitance value in the parallel LC resonant circuit can be adjusted. It can help the compensation subcircuit and the first capacitor to form a parallel LC resonant network, realize the parallel resonant network to reduce the transmission loss of the human body channel, and thus improve the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and wearable device participate.

In some feasible implementations of the second aspect, the signal circuit further includes a compensation switching subcircuit; and the compensation switching subcircuit is connected in series with the compensation subcircuit. Exemplarily, the compensation switching subcircuit may be connected in series between the first electrode and the compensation subcircuit, or the compensation switching subcircuit may also be connected in series between the second electrode and the compensation subcircuit.

The compensation switching subcircuit may include a first state and a second state. When the compensation switching subcircuit is in the first state, the first electrode is disconnected from the compensation subcircuit, or the second electrode is disconnected from the compensation subcircuit. Therefore, when the compensation switching subcircuit is in the first state, the current will not flow through the compensation subcircuit, making the compensation subcircuit ineffective. When the compensation switching subcircuit is in the second state, the first electrode is connected to the compensation subcircuit, and the second electrode is connected to the compensation subcircuit. Therefore, when the compensation switching subcircuit is in the second state, the current will flow through the compensation subcircuit to make the compensation subcircuit effective.

Therefore, when the second electrode of the smart ring is in contact with human skin and a first capacitor is equivalently formed between the human body and the second electrode, resulting in a high human channel transmission loss corresponding to the signal, the compensation switching subcircuit can be adjusted to the second state to make the compensation subcircuit effective. The compensation subcircuit and the first capacitor are used to form a parallel resonant network, thereby reducing the human channel transmission loss corresponding to signals of different frequencies and optimizing the reliability of HBC signal transmission of signals of specific frequencies in the HBC communication system involving signal circuits and wearable devices.

When the second electrode of the smart ring is not in contact with human skin, no first capacitor is formed between the human body and the second electrode, and the human body channel transmission loss corresponding to the signal is low, the compensation switching subcircuit can be adjusted to the first state to make the compensation subcircuit invalid, thereby maintaining the reliability of HBC signal transmission in the HBC communication system involving signal circuits and wearable devices.

In some feasible implementations of the second aspect, the signal circuit also includes a second transceiver subcircuit and a switching subcircuit. The second transceiver subcircuit includes a fifth signal terminal and a sixth signal terminal. The switching subcircuit is coupled to the first signal terminal, the second signal terminal, the fifth signal terminal and the sixth signal terminal, respectively. The switching subcircuit is also used to couple with the first electrode and the second electrode. When the switching subcircuit is in the first state, the first electrode is connected to the first signal terminal and disconnected from the fifth signal terminal, and the second electrode is connected to the second signal terminal and disconnected from the sixth signal terminal. When the switching subcircuit is in the second state, the first electrode is connected to the fifth signal terminal and disconnected from the first signal terminal, and the second electrode is connected to the sixth signal terminal and disconnected from the second signal terminal.

The second transceiver subcircuit may be a signal transceiver subcircuit of a current-coupled HBC. The second transceiver subcircuit may include a fifth signal terminal and a sixth signal terminal. The fifth signal terminal may be coupled to the first electrode so that the first electrode serves as a positive signal electrode of the smart ring; the sixth signal terminal may be coupled to the second electrode so that the second electrode serves as a negative signal electrode of the smart ring.

The switching subcircuit can be coupled to the first transceiver subcircuit, the second transceiver subcircuit, the first electrode, and the second electrode, respectively. When the switching subcircuit is in the first state, the first electrode and the second electrode are both coupled to the first transceiver subcircuit and disconnected from the second transceiver subcircuit; when the switching subcircuit is in the second state, the first electrode and the second electrode are both coupled to the second transceiver subcircuit and disconnected from the first transceiver subcircuit.

Exemplarily, when the switching subcircuit is in the first state, the switching subcircuit is used to connect the first signal terminal of the first transceiver subcircuit with the first electrode, disconnect the fifth signal terminal of the second transceiver subcircuit from the first electrode, and connect the second signal terminal of the first transceiver subcircuit with the second electrode, and disconnect the sixth signal terminal of the second transceiver subcircuit from the second electrode.

In this way, when the switching subcircuit is in the first state, the signal transceiver subcircuit as a capacitive coupling type HBC is coupled to the first electrode and the second electrode respectively. At this time, the smart ring can be a signal transceiver device of the capacitive coupling type HBC.

When the switching subcircuit is in the second state, the switching subcircuit is used to disconnect the first signal terminal of the first transceiver subcircuit from the first electrode, connect the fifth signal terminal of the second transceiver subcircuit to the first electrode, and disconnect the second signal terminal of the first transceiver subcircuit from the second electrode, and connect the sixth signal terminal of the second transceiver subcircuit to the second electrode.

In this way, when the switching subcircuit is in the second state, the signal transceiver subcircuit as a current-coupled HBC is coupled to the first electrode and the second electrode respectively. At this time, the smart ring can be a signal transceiver device of the current-coupled HBC.

In this embodiment, by switching sub-circuits, the smart ring can support capacitive coupling HBC communication and current coupling HBC communication in different time periods, thereby improving the communication diversity of the smart ring.

In a third aspect, a control method for a signal circuit is provided. The control method is applied to a signal circuit as in any one of the second aspect. The method comprises: when the second electrode is coupled with human skin to form a first capacitor, the signal circuit forms a parallel resonant network together with the first capacitor through a compensation subcircuit.

In some feasible implementations of the third aspect, the compensation subcircuit includes an inductor component. The signal circuit forms a parallel resonant network with the first capacitor through the compensation subcircuit, including: the signal circuit controls the closing or opening of at least one first switch to change the inductance value of the inductor component, so that the inductor component with the changed inductance value and the first capacitor form a parallel resonant network.

In some feasible implementations of the third aspect, the compensation subcircuit includes a first inductor, and the first inductor includes an adjustable inductor. The signal circuit forms a parallel resonant network together with the first capacitor through the compensation subcircuit, including: the signal circuit adjusts the inductance value of the first inductor so that the first inductor with the changed inductance value and the first capacitor form a parallel resonant network together.

In some feasible implementations of the third aspect, the compensation subcircuit further includes a capacitor component. The signal circuit forms a parallel resonant network together with the first capacitor through the compensation subcircuit, and further includes: the signal circuit controls the closing or opening of at least one second switch to change the capacitance value of the capacitor component to adjust the parallel capacitance value of the first capacitor and the capacitor component in the parallel resonant network.

In some feasible implementations of the third aspect, the compensation subcircuit includes a second capacitor, and the first inductor includes an adjustable capacitor. The signal circuit forms a parallel resonant network together with the first capacitor through the compensation subcircuit, and further includes: the signal circuit adjusts the capacitance value of the second capacitor to adjust the parallel capacitance value of the first capacitor and the second capacitor in the parallel resonant network.

In some feasible implementations of the third aspect, the method further includes: the signal circuit obtains the wearing information of the wearable device. The signal circuit determines the target frequency interval based on the wearing information. The signal circuit notifies the opposite device to communicate according to the target frequency interval. The signal circuit scans the signal in the target frequency interval, and uses the target frequency with a signal strength greater than a preset strength threshold as the human body communication frequency of the signal circuit; wherein the target frequency is a frequency in the target frequency interval.

In this implementation, the signal circuit can determine the target frequency interval of the signal that matches the user's current wearing posture and has a better communication effect based on the wearing information of the wearable device, and then determine the human body communication frequency in the target frequency interval, which can improve the efficiency of the signal circuit in determining the HBC signal frequency.

The technical effects of the third aspect can refer to the technical effects of the first aspect or the second aspect, and will not be repeated here.

In a fourth aspect, a circuit board is provided. The circuit board is applied to a wearable device as described in any one of the first aspects. The circuit board includes a signal circuit as described in any one of the second aspects.

The technical effects of the fourth aspect can refer to the technical effects of the first aspect or the second aspect, and will not be repeated here.

In a fifth aspect, a human body communication system is provided. The human body communication system includes a transmitting device and a receiving device that communicate with each other. The transmitting device includes a wearable device as described in any one of the first aspects. And/or, the receiving device includes a wearable device as described in any one of the first aspects.

The technical effects of the fifth aspect can refer to the technical effects of the first aspect or the second aspect, and will not be repeated here.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a three-dimensional diagram of a smart ring provided by some embodiments of the present application;

Fig. 2 is a cross-sectional view taken along line A-A' in Fig. 1;

FIG3 is a schematic structural diagram of the first electrode in FIG1 ;

FIG4 is another schematic diagram of the structure of the first electrode in FIG1 ;

FIG5 is another schematic diagram of the structure of the first electrode in FIG1 ;

FIG6 is a schematic diagram of another structure of the first electrode in FIG1 ;

FIG7 is an equivalent circuit diagram of the HBC communication system;

FIG8 is a schematic diagram of a structure of a signal circuit provided in some embodiments of the present application;

FIG9 is a curve diagram of the transmission loss of the human body channel between the human body and the second electrode under different conditions;

FIG10 is a schematic diagram of a structure of the signal circuit provided in FIG8 ;

FIG11 is a schematic diagram of the structure of an active inductor;

FIG12 is another schematic diagram of the structure of the compensation subcircuit in the signal circuit provided in FIG8 ;

FIG13 is another schematic diagram of the structure of the signal circuit provided in FIG8;

FIG14 is a schematic diagram of another structure of the compensation sub-circuit in the signal circuit provided in FIG8;

FIG15 is a curve diagram of the transmission loss of the human body channel when the human skin is in contact with the second electrode and the capacitor assembly/the second capacitor has different capacitance values;

FIG16 is a schematic diagram of the structure of a signal circuit provided in some other embodiments of the present application;

FIG17 is a schematic diagram of a structure of the signal circuit provided in FIG16;

FIG18 is a schematic diagram of the structure of a signal circuit provided in some other embodiments of the present application;

FIG19 is a schematic diagram of the structure of a signal circuit provided in some other embodiments of the present application;

FIG20 is a flow chart of a control method of a signal circuit provided in some embodiments of the present application;

Figures 21 to 27 show different wearing scenarios of the smart ring on a person's hand;

FIG28 is a flow chart of a control method of a signal circuit provided by other embodiments of the present application;

FIG. 29 is a flowchart of a signal circuit control method provided in some other embodiments of the present application.

DETAILED DESCRIPTION

The following will describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more.

When describing some embodiments, the expressions "connected", "connected" and their derivatives may be used. For example, when describing some embodiments, the term "connected" may be used to indicate that two or more components are in direct or indirect physical contact with each other. For example, A and B are connected, which may mean that A and B are connected, or that A and B are connected through other components. In addition, the term "coupled" may be a way of achieving electrical connection for signal transmission.

“At least one of A, B, and C” has the same meaning as “at least one of A, B, or C” and both include the following combinations of A, B, and C: A only, B only, C only, the combination of A and B, the combination of A and C, the combination of B and C, and the combination of A, B, and C.

“A and/or B” includes the following three combinations: A only, B only, and a combination of A and B.

As used herein, "about," "substantially," or "approximately" includes the stated value and an average value that is within an acceptable range of variation from the particular value as determined by one of ordinary skill in the art taking into account the measurements in question and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

HBC is also called intra-body communication (IBC), which can be understood as a short-range wireless communication method that uses human skin as a medium for information transmission (it can be understood as using the human body as a cable). Wearable devices can use signal circuits to achieve two-way data transmission. The above-mentioned signal circuit may include a signal transceiver subcircuit. The signal circuit can be connected to multiple electrodes (electrodes). For example, the wearable device may include 2 or more electrodes. The receiving end in the above-mentioned signal transceiver subcircuit can be used as an input device for the wearable device. The signal circuit can receive weak electrical signals transmitted by human skin through electrodes, thereby achieving signal reception; the transmitting end in the above-mentioned signal transceiver subcircuit can be used as an output device for the wearable device. The signal circuit can output weak electrical signals to human skin through electrodes, thereby achieving signal transmission. The above-mentioned transmitting end and receiving end are respectively coupled to at least one electrode, wherein the coupling method can be a wireless connection or a wired connection.

Research on the conductivity of human biological tissues shows that as the signal frequency increases, the dielectric constant of most living tissues or organs in the human body usually decreases significantly, while their conductivity increases significantly, which means that HBC should be performed at a higher frequency to reduce signal attenuation during communication.

However, when the signal frequency increases, the wavelength of the signal will become shorter accordingly. When the wavelength of the signal is close to the height of a person, the human body will act as a radio frequency antenna to emit electromagnetic waves to the surroundings, causing signal dissipation, and even causing the intensity of the signal coupled through the air to gradually exceed the intensity of the signal coupled through the human body. Therefore, signals with too high a frequency are not suitable for HBC.

Therefore, when performing HBC, the signal frequency can be selected within a frequency range greater than or equal to 10 KHz and less than or equal to 100 MHz.

To establish an HBC connection, two or more devices need to be coupled to the human body at the same time (including contacting the human body, or keeping a certain distance from the human body to achieve communication). In addition, different devices can communicate in a simplex or duplex mode.

According to the different coupling methods, HBC can be divided into two types: capacitive coupling (also called electric field coupling) and current coupling (also called waveguide coupling). Whether it is capacitive coupling or current coupling, the signal channel needs to be established between the electrodes and the human body during the signal transmission and reception process. The most intuitive difference between the two methods is whether the HBC electrodes must be in contact with the human body.

Capacitive coupling type is to establish a signal channel (communication loop) by capacitively coupling at least two electrodes of the transmitting device and at least two electrodes of the receiving device with the human body and the ground respectively, thereby realizing signal conduction. In the capacitive coupling type HBC, the electrodes of the transmitting device and the receiving device can be in contact with the human body, or the electrodes can be out of contact with the human body, and only need to keep a certain distance from the human body to achieve capacitive coupling.

For example, in a capacitive coupling HBC, the distance between the electrode and the human skin can be any value greater than or equal to 0 and less than or equal to 3 mm, for example, 0 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.2 mm, 2.8 mm, 3 mm, etc. Of course, in practical applications, the distance between the electrode and the human skin can also be specifically determined according to properties such as the signal frequency in the HBC.

The current coupling type is that at least one electrode of the transmitting device injects a weak current signal into the human body, and then at least one electrode of the receiving device receives the signal after being transmitted through the human body. That is, in the current coupling HBC method, all electrodes should be attached to and in contact with the human body.

Among them, for capacitive coupling HBC, the wearable device needs to have an electrode as a ground electrode coupled to the ground. Taking the wearable device as a smart ring as an example, the metal on the outer shell of the smart ring is usually used as the ground electrode. However, due to the complex wearing conditions of the smart ring, the ground electrode is easily affected by the proximity or contact of the surrounding fingers, resulting in a large signal attenuation of the signal transmitted by the human body in the capacitive coupling HBC, reducing the reliability of HBC signal transmission in the HBC communication system in which the wearable device participates. In order to overcome the problem of HBC signal attenuation and improve the reliability of HBC signal transmission, it is necessary to increase the signal transmission power of the wearable device, which will increase the power consumption of the wearable device and reduce the battery life of the wearable device.

Based on this, the embodiments of the present application provide a signal circuit and a control method thereof, and a wearable device.

The wearable devices provided in the embodiments of the present application may include but are not limited to smart headphones, smart watches, smart bracelets, smart glasses, augmented reality (AR) devices, virtual reality (VR) devices, electronic health detection equipment, smart rings, smart belts, smart belts, smart bracelets, smart anklets or smart necklaces and other wearable electronic products.

For ease of understanding, the following description will be made using a smart ring as a wearable device, but this should not be limiting, and it should be considered that each example described below can also be applied to other wearable devices such as smart watches and smart glasses.

Fig. 1 shows a stereoscopic view of a smart ring provided in some embodiments of the present application; Fig. 2 shows a cross-sectional view formed along line A-A’ in Fig. 1 .

As shown in Figures 1 and 2, the smart ring 100 may include a first electrode 110, a second electrode 120, an insulator 130 and a circuit board 140. The insulator 130 may be located between the first electrode 110 and the second electrode 120 to insulate the first electrode 110 and the second electrode 120 from each other.

As shown in FIG. 1 and FIG. 2 , the inner surface of the first electrode 110 may belong to the inner surface of the smart ring 100. The inner surface of the smart ring 100 is the surface in contact with the finger wearing the smart ring 100, and the shape of the inner surface of the smart ring 100 may be cylindrical. The inner surface of the first electrode 110 may serve as part of the inner surface of the smart ring 100.

When the smart ring 100 adopts capacitive coupling HBC, the first electrode 110 can be used as a signal electrode. When the smart ring is used as a sending device of HBC signals, the signal electrode can send signals to human skin; when the smart ring is used as a receiving device of HBC signals, the signal electrode can receive signals transmitted by human skin.

The first electrode 110 may be at least partially an arc-shaped structure, so that the inner surface of the first electrode 110 may also be an arc-shaped surface, adapted to the shape of the finger wearing the smart ring 100, and in contact with the finger wearing the smart ring 100, so as to achieve coupling between the first electrode 110 and human skin. Exemplarily, the first electrode 110 may be partially an arc-shaped structure and the other partially a flat plate structure (or other structures, which are not limited in the embodiments of the present application); or, the first electrode 110 may be entirely an arc-shaped structure.

The inner surface of the first electrode 110 may be referred to as a first arc-shaped surface. As shown in FIG2 , the central angle of the first arc-shaped surface may be greater than 180°.

Exemplarily, the first electrode 110 may include a metal material, such as at least one of copper, tungsten, silver, aluminum, etc. The embodiments of the present application do not limit the specific type of the metal material.

The insulator 130 may be located outside the first electrode 110. It is understandable that the insulator 130 may be located on the side of the first electrode 110 away from the finger wearing the smart ring 100. The insulator 130 may cover the outer surface of the first electrode 110. Exemplarily, if the first electrode 110 is entirely an arc-shaped structure, the insulator 130 may cover the outer surface of the arc-shaped structure. Exemplarily, if part of the first electrode 110 is an arc-shaped structure and the other part is a flat plate structure, the insulator 130 may cover the outer surface of the arc-shaped structure and the outer surface of the flat plate structure.

In some examples, the insulator 130 may include a flexible material. The flexible material may be a flexible insulating material such as rubber or foam, which is not limited in the embodiments of the present application. The insulator 130 may be formed into a closed shape as a buffer layer between the finger wearing the smart ring 100 and the housing 100a of the smart ring 100, thereby improving the comfort of the user wearing the smart ring 100.

As shown in FIG. 2 , the insulator 130 may be a ring-shaped structure, and the inner ring surface of the insulator 130 covers the outer surface of the first electrode 110 .

In some examples, as shown in FIG. 2 , the insulator 130 is provided with a recess 131, and the first electrode 110 can be accommodated in the recess 131, so that the inner surface of the first electrode 110 and the inner ring surface of the insulator 130 form a continuous surface. In this way, the inner surface of the first electrode 110 and the inner ring surface of the insulator 130 can be used together as the inner surface of the smart ring 100. In addition, the recess 131 can avoid the problem of uncomfortable wearing of the smart ring 100 caused by the step difference between the first electrode 110 and the inner ring surface of the insulator 130, thereby further improving the comfort of the user wearing the smart ring 100.

In some examples, in order to prevent friction loss between the first electrode 110 and the finger, the smart ring 100 may further include a protective film (not shown). The protective film may cover the surface of the first electrode 110 in contact with the finger, that is, the protective film may cover the surface of the first electrode 110 away from the insulator 130.

In the case where the smart ring 100 includes a protective film, the first electrode 110 does not directly contact the finger, but is indirectly coupled to the finger by being close to the finger.

The second electrode 120 is located on a side of the insulator 130 away from the first electrode 110. When the smart ring 100 adopts capacitive coupling HBC, the second electrode 120 can be used as a ground electrode.

In some examples, the second electrode 120 may be a part of the housing 100a of the smart ring 100. Exemplarily, the housing 100a of the smart ring 100 may include the first electrode 110 and a plastic housing (or a housing made of other materials, which is only an example here, and the embodiments of the present application do not limit the housing material). The plastic housing and the first electrode 110 are connected to each other, and the plastic housing may limit the position movement of the first electrode 110.

In other examples, the second electrode 120 can also be used as the entire housing 100a of the smart ring 100. It can be understood that, as shown in FIG. 2, the second electrode 120 can be enclosed in a closed shape as the housing 100a of the wearable device 100, and the first electrode 110 and the insulator 130 are located on the inner side of the second electrode 120. In this case, the housing 100a is a full metal housing. The full metal housing can be an integrally formed structure, and the housing has no gaps.

Exemplarily, the second electrode 120 may include a metal material, such as at least one of copper, tungsten, silver, aluminum, etc. The embodiments of the present application do not limit the specific type of the metal material.

The inner surface of the second electrode 120 may be referred to as a second arcuate surface. As shown in FIG2 , the central angle of the second arcuate surface is 360°. The central angle of the second arcuate surface may be greater than the central angle of the first arcuate surface.

The housing 100a of the smart ring 100 may be designed with a top platform 120a having a plane. Symbols, patterns, or other decorations may be printed on the plane of the top platform 120a. The top platform 120a can help the user identify the wearing direction of the smart ring 100, and avoid reducing the reliability of HBC signal transmission in the HBC communication system in which the smart ring 100 participates due to the user wearing the smart ring in the wrong direction.

The housing 100a of the smart ring 100 has a receiving space 100b inside. The receiving space 100b is located between the inner contour of the second electrode 120 and the outer contour of the second electrode 120. The insulator 130 may be partially or entirely located in the receiving space 100b. When the insulator 130 is entirely located in the receiving space 100b, the first electrode 110 may be partially located in the receiving space 100b.

In this way, the insulator 130 is at least partially located in the accommodating space 100b of the second electrode 120, which can optimize the layout space of the smart ring 100, facilitate the miniaturized design of the smart ring 100, and improve the portability of the wearable device.

The circuit board 140 is located on a side of the insulator 130 away from the first electrode 110. It can be understood that the circuit board 140 is located outside the insulator 130. The circuit board 140 can be located in the accommodating space 100b. Exemplarily, the circuit board 140 may include a first circuit board segment 141, a second circuit board segment 142, and a third circuit board segment 143, and the second circuit board segment 142 and the third circuit board segment 143 are respectively connected to opposite ends of the first circuit board segment 141. Among them, the extension direction of the first circuit board segment 141 and the extension direction of the second circuit board segment 142 intersect each other, and the extension direction of the first circuit board segment 141 and the extension direction of the third circuit board segment 143 intersect each other.

Exemplarily, the second circuit board segment 142 and the third circuit board segment 143 are symmetrically arranged along an axis perpendicular to the first circuit board segment 141 .

In some examples, the same circuit board segment may be coupled to the first electrode 110 and the second electrode 120. For example, the first circuit board segment 141 is coupled to the first electrode 110 and the second electrode 120 at the same time. In other examples, different circuit board segments may be coupled to the first electrode 110 and the second electrode 120, respectively. For example, as shown in FIG. 2 , the first circuit board segment 141 is coupled to the second electrode 120, and the third circuit board segment 143 is coupled to the first electrode 110.

The circuit board 140 and the second electrode 120 may be coupled by directly contacting the second electrode 120 through the conductive structure 144, thereby coupling the circuit board 140 and the second electrode 120. The circuit board 140 and the first electrode 110 may be coupled by using the conductive structure 144 to contact the first electrode 110 through the insulator 130, thereby coupling the circuit board 140 and the first electrode 110.

The conductive structure 144 may be a metal spring, a conductive cloth, a conductive adhesive, a metal wire or other structure capable of conducting electrical signals, which is not limited in the embodiments of the present application.

In this way, by accommodating the circuit board 140 in the accommodating space 100b of the second electrode 120, it is beneficial to the miniaturized design of the smart ring 100. The first electrode 110 and the second electrode 120 can also be coupled to the circuit board 140 through the conductive structure 144, thereby improving the reliability of the wearable device.

As shown in FIG. 2 , the smart ring 100 may further include a battery 150 . The battery 150 may be located in the accommodation space 100 b inside the housing 100 a . The shape of the battery 150 may also be an arc shape. Exemplarily, the battery 150 may be located between the top platform 120 a and the insulator 130 .

The circuit board 140 is also coupled to the battery 150, and the battery 150 provides an operating voltage to the circuit board 140. The battery 150 can be a dry cell (also known as a disposable battery) or a rechargeable battery. In the case where the battery 150 is a rechargeable battery, a charging interface for charging the battery 150 can also be provided on the housing 100a of the smart ring 100.

Figure 3 shows a structural schematic diagram of the first electrode in Figure 1; Figure 4 shows another structural schematic diagram of the first electrode in Figure 1; Figure 5 shows another structural schematic diagram of the first electrode in Figure 1; Figure 6 shows another structural schematic diagram of the first electrode in Figure 1.

In the case where the smart ring 100 does not include other sensors, the shape of the first electrode 110 can be as shown in FIG3, that is, there is no opening between the first electrodes 110. In the case where the smart ring 100 also includes other sensors (e.g., light-emitting diodes and photoelectric receiving elements for measuring blood oxygen) that need to contact human skin (e.g., fingers wearing the smart ring 100), the first electrode 110 can be provided with a rectangular opening 11a as shown in FIG4, or a circular opening 11b as shown in FIG5, or a fracture 11c as shown in FIG6. The specific opening shape may depend on the shape of the sensor, which is not limited in the embodiments of the present application.

Among them, the above-mentioned fracture 11c can divide a first electrode 110 into two sub-electrodes 111, as shown in Figure 6, and the two sub-electrodes 111 can be coupled through a connecting line 112; or, the two sub-electrodes 111 can also be coupled to the circuit board 140 through a connector respectively, and then coupled through a signal line on the circuit board 140, thereby realizing the coupling between the two sub-electrodes 111.

The number of openings and/or breaks in a first electrode 111 may be one, two, or more, which is not limited in the embodiments of the present application.

FIG7 shows an equivalent circuit diagram of an HBC communication system. An embodiment of the present application further provides an HBC communication system. The transmitting device in the HBC communication system may be a wearable device provided in an embodiment of the present application; and/or, the receiving device in the HBC communication system may be a wearable device provided in an embodiment of the present application.

FIG7 takes the HBC communication system using capacitive coupling HBC as an example, the smart ring 100 can be used as a receiving device of the HBC communication system, the smart watch 300 can be used as a sending device of the HBC communication system, and the human body is used as a transmission medium between the sending device and the receiving device. That is, the smart watch 300 is a sending device, and the smart ring 100 is a receiving device. The smart watch 300 is the opposite device of the smart ring 100.

As shown in FIG7 , the smart watch 300 transmits the HBC signal to the human skin through electrodes. The HBC signal is transmitted to the smart ring 100 on the human skin. The electrodes of the smart ring 100 collect the HBC signal, thereby completing one transmission of the HBC signal.

Among them, since the human body has a lossy effect on the transmission of electrical signals, the human body can be equivalent to multiple electronic devices according to the different positions and functions of the human body. Exemplarily, as shown in Figure 7, the HBC communication system may include multiple electronic devices equivalent to the human body, and the multiple electronic devices include a first impedance Z1, a second impedance Z2, a third impedance Z3, a fourth impedance Z4, and a fifth impedance Z5. Among them, the first impedance Z1 can represent the impedance formed by the contact between the smart watch 300 and the human skin; the second impedance Z2 can represent the impedance of the human skin on the signal sending side; the third impedance Z3 can represent the impedance formed by the contact between the smart ring 100 and the human skin; the fourth impedance Z4 can represent the impedance of the human skin on the signal receiving side; the fifth impedance Z5 can represent the impedance formed between the subcutaneous tissue of the human body and the earth. Exemplarily, the fifth impedance Z5 includes the impedance of the subcutaneous tissue of the human body and the impedance between the subcutaneous tissue and the foot.

Secondly, the HBC communication system may also include multiple electronic devices equivalent to the contact between the human body and the device. Exemplarily, as shown in Figure 7, the HBC communication system may include a first contact capacitor C1 (hereinafter referred to as the first capacitor C1), a second contact capacitor C02, a third contact capacitor C03 and a fourth contact capacitor C04. Among them, the first contact capacitor C1 can represent the capacitance between the ground electrode of the smart ring 100 and the human skin; the second contact capacitor C02 can represent the capacitance between the human skin and the earth on the signal receiving side; the third contact capacitor C03 can represent the capacitance between the ground electrode of the smart watch 300 and the human skin; the fourth contact capacitor C04 can represent the capacitance between the human skin and the earth on the signal sending side.

In addition, the HBC communication system may also include an electronic device equivalent to the contact between the human body and the earth, and an electronic device equivalent to the contact between the device and the earth. Exemplarily, as shown in FIG7 , the HBC communication system may include a fifth contact capacitor C05, a sixth contact capacitor C06, and a seventh contact capacitor C07. Among them, the fifth contact capacitor C05 may represent the capacitance between the ground electrode of the smart watch 300 and the earth; the sixth contact capacitor C06 may represent the capacitance between the human foot and the earth; and the seventh contact capacitor C07 may represent the capacitance between the ground electrode of the smart ring 100 and the earth.

In some other examples, the receiving device and the sending device in the HBC communication system may both be the smart ring 100 described above.

Figure 8 shows a structural schematic diagram of a signal circuit provided in some embodiments of the present application; Figure 9 shows a curve chart of the human body channel transmission loss between the human body and the second electrode under different conditions; Figure 10 shows a structural schematic diagram of the signal circuit provided in Figure 8; Figure 11 shows a structural schematic diagram of an active inductor; Figure 12 shows another structural schematic diagram of a compensation subcircuit in the signal circuit provided in Figure 8.

As shown in FIG8 , an embodiment of the present application provides a signal circuit 200. The signal circuit 200 may be located on a circuit board 140 in a wearable device 100. The signal circuit 200 may include a first transceiver subcircuit 210 and a compensation subcircuit 220.

The first transceiver subcircuit 210 may be a capacitive coupling type HBC signal transceiver subcircuit. The first transceiver subcircuit 210 may include a first signal terminal X1 and a second signal terminal X2. The first signal terminal X1 may be coupled to the first electrode 110, so that the first electrode 110 serves as a signal electrode of the smart ring 100; the second signal terminal X2 may be coupled to the second electrode 120, and coupled to the ground terminal GND, so that the second electrode 120 serves as a ground electrode of the smart ring 100.

The compensation subcircuit 220 may include a third signal terminal X3 and a fourth signal terminal X4. The third signal terminal X3 may be coupled to the first electrode 110, and the fourth signal terminal X4 may be coupled to the second electrode 120. It can be understood that the compensation subcircuit 220 and the first transceiver subcircuit 210 are connected in parallel.

When the second electrode 120 is in contact with human skin (for example, a finger other than the finger wearing the smart ring 100), it has been previously described that the contact between the second electrode 120 and the human skin can be equivalent to forming a capacitor (i.e., the first capacitor C1 mentioned above). The capacitance value of the first capacitor C1 formed equivalently may also be different depending on the degree of contact between the human skin and the second electrode 120.

It should be noted that the first capacitor C1 does not belong to the signal circuit. The first capacitor C1 is an electronic device equivalent to the contact between the second electrode 120 and the human skin.

In the case where there is no contact between the second electrode 120 and the human skin, and there is no mutual coupling between the ground electrode and the human skin, the human channel transmission loss is as shown in Curve 1 in FIG9 . In other words, Curve 1 corresponds to the case where the first capacitor C1 does not exist in the HBC communication system. In the case where the second electrode 120 is in contact with the human skin (for example, a finger other than the finger wearing the smart ring 100), and there is mutual coupling between the ground electrode and the human skin, the human signal transmission loss is as shown in Curve 2 in FIG9 . In other words, Curve 2 corresponds to the case where the first capacitor C1 exists in the HBC communication system.

It can be seen from Figure 9 that the average loss corresponding to curve 1 is less than the average loss corresponding to curve 2. It can be understood that the first capacitor C1 equivalently formed by the second electrode 120 in the signal circuit and the human skin contact will increase the human channel transmission loss, thereby resulting in low reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

In the embodiment of the present application, the compensation subcircuit 220 is used to form a parallel resonant network together with the first capacitor C1. The parallel resonant network can be equivalent to an open circuit in the signal circuit 200, thereby disconnecting the first capacitor C1 from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

When the second electrode 120 is in contact with human skin, the ground electrode is mutually coupled with the human body, and the signal circuit 200 includes the compensation subcircuit 220, the human body channel transmission loss is shown as curve 3 in FIG9. In other words, curve 3 corresponds to the case where the first capacitor C1 and the compensation subcircuit 220 exist in the HBC communication system.

It can be seen from Figure 9 that the average loss corresponding to curve 3 is less than the average loss corresponding to curve 2. It can be understood that adding the compensation subcircuit 220 in the signal circuit can reduce the human body channel transmission loss, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and the wearable device participate.

For the signal circuit shown in Figure 8, the embodiment of the present application provides a control method for the signal circuit. When the second electrode 120 contacts the human skin and is coupled to form a first capacitor C1, the signal circuit forms a parallel resonant network with the first capacitor C1 through the compensation subcircuit 220.

In this way, the parallel resonant network can be equivalent to an open circuit in the signal circuit 200, thereby disconnecting the first capacitor C1 from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

In some examples, as shown in FIG. 10 , the compensation subcircuit 220 may include an inductor (hereinafter referred to as the first inductor L1 for ease of distinction). The first end of the first inductor L1 is coupled to the first electrode 110, and the second end of the first inductor L1 is coupled to the second electrode 120. The first inductor L1 and the first capacitor C1 are substantially equivalent to a parallel relationship, thereby forming a parallel LC (L represents the first inductor, C represents the first capacitor) resonant network.

The parallel LC resonant network can be equivalent to an open circuit in the signal circuit 200, thereby disconnecting the first capacitor C1 from the human body channel, reducing the transmission loss of the human body channel, and thus improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

By selecting the first inductor L1 with different inductance values, the inductance parameter in the LC resonant network formed by the first capacitor C1 and the first inductor L1 being connected in parallel can be adjusted. Alternatively, the first inductor L1 can be an adjustable inductor with an adjustable inductance value, and by adjusting the capacitance value of the first inductor L1, the inductance parameter in the LC resonant network formed by the first capacitor C1 and the first inductor L1 being connected in parallel can also be adjusted.

Exemplarily, the signal circuit 200 may further include a controller (not shown). The controller adjusts the inductance of the first inductor L1 so that the first inductor L1 with changed inductance and the first capacitor C1 together form a parallel resonant network.

Exemplarily, as shown in FIG11 , the first inductor L1 may include an active inductor. The active inductor may include a transistor Gm1, a transistor Gm2, and a capacitor Cx. The transistor Gm1 and the transistor Gm2 may also be referred to as gyrators. By adjusting at least one of the transistor Gm1, the transistor Gm2, and the capacitor Cx, the inductance value of the active inductor may be adjusted.

Of course, the first inductor L1 may also adopt other inductor types or circuits to adjust the inductance value, which is not limited in the embodiments of the present application.

In some examples, as shown in FIG. 12 , the compensation subcircuit 220 may include a plurality of inductors (for ease of distinction, the plurality of inductors are collectively referred to as an inductor assembly UL, wherein a single inductor is referred to as a second inductor L2). The plurality of second inductors L2 are connected in series with each other, for example, the first end of the first second inductor L2 in the plurality of second inductors L2 is coupled to the first electrode 110 as the third signal end X3, the second end of the first second inductor L2 is coupled to the first end of the second second inductor L2, the second end of the second second inductor L2 is coupled to the first end of the third second inductor L2, and so on ... until the second end of the last second inductor L2 is coupled to the second electrode 120 as the fourth signal end X4.

In addition, as shown in FIG12 , each second inductor L2 may be connected in parallel with a first switch K1. The first end of the second inductor L2 is coupled to the first end of the first switch K1, and the second end of the second inductor L2 is coupled to the second end of the first switch K1. When the first switch K1 is in a closed state, the first end of the first switch K1 is connected to the second end of the first switch K1; when the first switch K1 is in an open state, the first end of the first switch K1 is disconnected from the second end of the first switch K1.

The multiple second inductors L2 may be multiple inductors with equal inductance values, or may be multiple inductors with unequal inductance values, which is not limited in the embodiments of the present application.

In a set of mutually parallel selection units and second inductors L2, when the first switch K1 in the selection unit is in an open state, the selection unit is in an open circuit state. In this way, the current will pass through the second inductor L2, so that the second inductor L2 will be effective in the compensation sub-circuit 220. When the first switch K1 in the selection unit is in a closed state, the selection unit is in a pass state. In this way, the current will not pass through the second inductor L2 but through the selection unit, so that the second inductor L2 will not be effective in the compensation sub-circuit 220.

By switching the state of the first switch K1 in each group of mutually parallel selection units and second inductors L2, it is possible to control whether the second inductor L2 in the group of mutually parallel selection units and second inductors L2 is effective, thereby controlling whether the multiple second inductors L2 in the compensation sub-circuit 220 are effective. In other words, by controlling the states of the multiple first switches K1, the effective number of the multiple second inductors L2 in the compensation sub-circuit 220 can be adjusted.

Exemplarily, the signal circuit 200 may further include a controller (not shown). The controller is coupled to the plurality of first switches K1 and is used to control the state switching of each first switch K1. It can be understood that the controller may control each first switch K1 to be in a closed state or an open state.

As described above, the plurality of second inductors L2 are connected in series with each other. Therefore, by controlling the states of the plurality of first switches K1 to control the effective number of the plurality of second inductors L2, the inductance value of the inductor assembly UL (i.e., the inductance value of the compensation subcircuit 220) can be adjusted. In this way, the compensation subcircuit 220 and the first capacitor C1 can be helped to form a parallel LC resonant network, and the parallel LC resonant network can be used to reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and the wearable device participate.

For the signal circuit shown in FIG12 , an embodiment of the present application provides a control method for the signal circuit, in which the compensation subcircuit 220 and the first capacitor C1 form a parallel resonant network together, and the inductance value of the inductor component UL can be changed by controlling at least one first switch K1 to switch from a closed state to an open state, or from an open state to a closed state. In this way, the compensation subcircuit 220 and the first capacitor C1 can form a parallel LC resonant network together, and the parallel LC resonant network can reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and the wearable device participate.

FIG. 13 shows another structural schematic diagram of the signal circuit provided in FIG. 8 ; FIG. 14 shows another structural schematic diagram of the compensation subcircuit in the signal circuit provided in FIG. 8 .

In some examples, as shown in FIG13 , the compensation subcircuit 220 may further include a capacitor (hereinafter referred to as a second capacitor C2 for the sake of distinction). The first plate of the second capacitor C2 is coupled to the first electrode 110 , and the second plate of the second capacitor C2 is coupled to the second electrode 120 and the ground terminal GND.

Taking the compensation subcircuit 220 including the second capacitor C2 and the first inductor L1 as an example, the second capacitor C2 and the first inductor L1 are connected in parallel to each other in the compensation subcircuit 220. As described above, the first inductor L1 is connected in parallel to the first capacitor C1, and here the second capacitor C2 is connected in parallel to the first inductor L1, so the first capacitor C1 and the second capacitor C2 are connected in parallel.

By selecting a second capacitor C2 with different capacitance values, the capacitance value of the first capacitor C1 and the second capacitor C2 connected in parallel can be adjusted. Alternatively, the second capacitor C2 can be an adjustable capacitor with an adjustable capacitance value, and by adjusting the capacitance value of the second capacitor C2, the capacitance value of the first capacitor C1 and the second capacitor C2 connected in parallel can also be adjusted.

Exemplarily, the signal circuit 200 further includes a controller. The controller adjusts the capacitance value of the second capacitor C2 to adjust the parallel capacitance value of the first capacitor C1 and the second capacitor C2 in the parallel resonant network.

In this way, the compensation subcircuit 220 can adjust the capacitance value in the parallel LC resonant circuit through the second capacitor C2, which can help the compensation subcircuit 220 and the first capacitor C1 to form a parallel LC resonant network, thereby realizing the parallel LC resonant network to reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

In some examples, as shown in FIG14 , the compensation subcircuit 220 may further include a plurality of capacitors (for ease of distinction, the plurality of capacitors are collectively referred to as a capacitor component UC, wherein a single capacitor is referred to as a third capacitor C3). The first plate of each third capacitor C3 is coupled to the first electrode 110, and the second plate of each third capacitor C3 is coupled to the second electrode 120 and the ground terminal GND.

In addition, a second switch K2 may be connected in series between each third capacitor C3 and the first electrode 110. The first end of the second switch K2 is coupled to the first electrode 110, and the second end of the second switch K2 is coupled to the first plate of the third capacitor. Of course, the second switch may also be connected in series between the third capacitor and the ground terminal.

When the second switch K2 is in a closed state, the first end of the second switch K2 is connected to the second end of the second switch K2; when the second switch K2 is in an open state, the first end of the second switch K2 is disconnected from the second end of the second switch K2.

The multiple third capacitors C3 may be multiple capacitors with equal capacitance values, or may be capacitors with unequal capacitance values, which is not limited in the embodiments of the present application.

In a set of the second switch K2 and the third capacitor C3 connected in series, when the second switch K2 is in an open state, the circuit between the third capacitor C3 and the first electrode 110 is in an open state. In this way, the current will not be conducted to the third capacitor C3, so that the third capacitor C3 will not be effective in the compensation sub-circuit 220. When the second switch K2 is in a closed state, the circuit between the third capacitor C3 and the first electrode 110 is in a conductive state. In this way, the current can be conducted to the third capacitor C3, so that the third capacitor C3 will be effective in the compensation sub-circuit 220.

The effective plurality of third capacitors C3 are connected in parallel with each other, so the capacitance value of the capacitor assembly UC can be calculated based on the capacitance values of the effective plurality of third capacitors C3.

By switching the state of the second switch K2 in each group of second switches K2 and third capacitors C3 connected in series, it is possible to control whether the third capacitor C3 in the group of second switches K2 and third capacitors C3 connected in series is effective, thereby controlling whether the multiple third capacitors C3 in the compensation sub-circuit 220 are effective. In other words, by controlling the states of the multiple second switches K2, it is possible to adjust the effective number of the multiple third capacitors C3 in the capacitor assembly UC, thereby adjusting the capacitance value of the capacitor assembly UC.

Exemplarily, the signal circuit 200 may further include a controller (not shown). The controller is coupled to the plurality of second switches K2 and is used to control the state switching of each second switch K2. It can be understood that the controller may control each second switch K2 to be in a closed state or an open state.

The capacitor component UC is similar to the second capacitor C2 and is also connected in parallel with the first capacitor C1. Therefore, by adjusting the capacitance value of the capacitor component UC, the capacitance value in the parallel LC resonant circuit can be adjusted. It can help the compensation subcircuit 220 and the first capacitor C1 to form a parallel LC resonant network, and realize the parallel resonant network to reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

For the signal circuit shown in FIG14 , an embodiment of the present application provides a control method for the signal circuit, in which the compensation subcircuit 220 is used to form a parallel resonant network together with the first capacitor C1, and the capacitance value of the capacitor component UC can be changed by controlling at least one second switch K2 to switch from a closed state to an open state, or from an open state to a closed state. In this way, the compensation subcircuit 220 and the first capacitor C1 can form a parallel LC resonant network together, and the parallel resonant network can reduce the transmission loss of the human body channel, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

FIG. 15 is a graph showing the transmission loss of a human body channel when human skin is in contact with the second electrode and the capacitor assembly/second capacitor has different capacitance values.

When the capacitance value of the capacitor assembly/the second capacitor is 0pF, the human body channel transmission loss is shown as curve 3a in Figure 15; when the capacitance value of the capacitor assembly/the second capacitor is 5pF, the human body channel transmission loss is shown as curve 3b in Figure 15; when the capacitance value of the capacitor assembly/the second capacitor is 10pF, the human body channel transmission loss is shown as curve 3c in Figure 15.

As can be seen from Figure 15, by changing the capacitance value of the capacitor assembly/the second capacitor, the capacitance value in the parallel LC resonant circuit can be adjusted, so that the compensation sub-circuit 220 and the first capacitor C1 together form a parallel LC resonant network, thereby reducing the human body channel transmission loss corresponding to HBC signals of different frequencies, and optimizing the reliability of HBC signal transmission of specific frequencies in the HBC communication system involving the signal circuit 200 and the wearable device 100.

FIG. 16 is a schematic diagram showing the structure of signal circuits provided in other embodiments of the present application; FIG. 17 is a schematic diagram showing a structure of the signal circuit provided in FIG. 16 .

In some examples, as shown in FIG16 , the signal circuit 200 may further include a compensation switching subcircuit 230. The compensation switching subcircuit 230 is connected in series with the compensation subcircuit 220. Exemplarily, the compensation switching subcircuit 230 may be connected in series between the first electrode 110 and the compensation subcircuit 220, or the compensation switching subcircuit 230 may also be connected in series between the second electrode 120 and the compensation subcircuit 220 (as shown in FIG16 ).

The compensation switching subcircuit 230 may include a first state and a second state. When the compensation switching subcircuit 230 is in the first state, the first electrode 110 is disconnected from the compensation subcircuit 220, or the second electrode 120 is disconnected from the compensation subcircuit 220. Therefore, when the compensation switching subcircuit 230 is in the first state, the current will not flow through the compensation subcircuit 220, making the compensation subcircuit 220 ineffective. When the compensation switching subcircuit 230 is in the second state, the first electrode 110 is connected to the compensation subcircuit 220, and the second electrode 120 is connected to the compensation subcircuit 220. Therefore, when the compensation switching subcircuit 230 is in the second state, the current will flow through the compensation subcircuit 22, making the compensation subcircuit 220 effective.

It can be seen that by adjusting the state of the compensation switching sub-circuit 230 , the compensation sub-circuit 220 in the signal circuit 200 can be enabled or disabled.

Therefore, when the second electrode of the smart ring 100 is in contact with human skin and a first capacitor is equivalently formed between the human body and the second electrode, resulting in a high human channel transmission loss corresponding to the signal, the compensation switching subcircuit 230 can be adjusted to the second state to make the compensation subcircuit 220 effective. The compensation subcircuit 220 and the first capacitor together form a parallel resonant network, thereby reducing the human channel transmission loss corresponding to signals of different frequencies and optimizing the reliability of HBC signal transmission of signals of specific frequencies in the HBC communication system involving signal circuits and wearable devices.

When the second electrode of the smart ring 100 is not in contact with human skin, no first capacitor is formed between the human body and the second electrode, and the human body channel transmission loss corresponding to the signal is low, the compensation switching subcircuit 230 can be adjusted to the first state to make the compensation subcircuit 220 invalid, thereby maintaining the reliability of HBC signal transmission in the HBC communication system involving signal circuits and wearable devices.

In some examples, as shown in FIG17 , the compensation switching subcircuit 230 may include a third switch K3. When the compensation switching subcircuit 230 is connected in series between the first electrode 110 and the compensation subcircuit 220, a first end of the third switch K3 is coupled to the first electrode 110, and a second end of the third switch K3 is coupled to the compensation subcircuit 220. When the compensation switching subcircuit 230 is connected in series between the second electrode 120 and the compensation subcircuit 220, a first end of the third switch K3 is coupled to the compensation subcircuit 220, and a second end of the third switch K3 is coupled to the second electrode 120 (as shown in FIG17 ).

When the third switch K3 is in a closed state, the first end of the third switch K3 is connected to the second end of the third switch K3, so that the compensation switching subcircuit 230 is in the second state. In this way, the compensation subcircuit 220 takes effect, and the compensation subcircuit 220 and the first capacitor C1 together form a parallel resonant network, thereby reducing the human body channel transmission loss corresponding to HBC signals of different frequencies, and optimizing the reliability of HBC signal transmission of HBC signals of specific frequencies in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

When the third switch K3 is in the off state, the first end of the third switch K3 is disconnected from the second end of the third switch K3, so that the compensation switching subcircuit 230 is in the first state. In this way, the compensation subcircuit 220 fails, and the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate is maintained.

FIG. 18 is a schematic diagram showing the structure of a signal circuit provided by some other embodiments of the present application; FIG. 19 is a schematic diagram showing the structure of a signal circuit provided by some other embodiments of the present application.

As shown in FIG. 18 , the signal circuit 200 may further include a second transceiver sub-circuit 240 and a switch sub-circuit 250 .

The second transceiver subcircuit 240 may be a signal transceiver subcircuit of a current-coupled HBC. The second transceiver subcircuit 240 may include a fifth signal terminal X5 and a sixth signal terminal X6. The fifth signal terminal X5 may be coupled to the first electrode 110, so that the first electrode 110 serves as a positive signal electrode of the smart ring 100; the sixth signal terminal X6 may be coupled to the second electrode 120, so that the second electrode 120 serves as a negative signal electrode of the smart ring 100.

The switching subcircuit 250 may be respectively coupled to the first transceiver subcircuit 210, the second transceiver subcircuit 240, the first electrode 110, and the second electrode 120. When the switching subcircuit 250 is in the first state, the first electrode 110 and the second electrode 120 are both coupled to the first transceiver subcircuit 210 and disconnected from the second transceiver subcircuit 240; when the switching subcircuit 250 is in the second state, the first electrode 110 and the second electrode 120 are both coupled to the second transceiver subcircuit 240 and disconnected from the first transceiver subcircuit 240.

Exemplarily, when the switching subcircuit 250 is in the first state, the switching subcircuit 250 is used to connect the first signal terminal X1 of the first transceiver subcircuit 210 to the first electrode 110, disconnect the fifth signal terminal X5 of the second transceiver subcircuit 240 from the first electrode 110, and connect the second signal terminal X2 of the first transceiver subcircuit 210 to the second electrode 120, and disconnect the sixth signal terminal X6 of the second transceiver subcircuit 240 from the second electrode 120.

In this way, when the switching subcircuit 250 is in the first state, the signal transceiver subcircuit as a capacitive coupling type HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of a capacitive coupling type HBC.

When the switching subcircuit 250 is in the second state, the switching subcircuit 250 is used to disconnect the first signal terminal X1 of the first transceiver subcircuit 210 from the first electrode 110, connect the fifth signal terminal X5 of the second transceiver subcircuit 240 to the first electrode 110, and disconnect the second signal terminal X2 of the first transceiver subcircuit 210 from the second electrode 120, and connect the sixth signal terminal X6 of the second transceiver subcircuit 240 to the second electrode 120.

In this way, when the switching subcircuit 250 is in the second state, the signal transceiver subcircuit as a current-coupled HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of the current-coupled HBC.

In some examples, as shown in FIG. 18 , the switching subcircuit 250 includes a first terminal D1 , a second terminal D2 , a third terminal D3 , a fourth terminal D4 , a fifth terminal D5 , and a sixth terminal D6 .

The first terminal D1 is coupled to the first signal terminal X1 of the first transceiver sub-circuit 210, the second terminal D2 is coupled to the second signal terminal X2 of the first transceiver sub-circuit 210, the third terminal D3 is coupled to the fifth signal terminal X5 of the second transceiver sub-circuit 240, the fourth terminal D4 is coupled to the sixth signal terminal X6 of the second transceiver sub-circuit 240, the fifth terminal D5 is coupled to the first electrode 110, and the sixth terminal D6 is coupled to the second electrode 120.

When the switching subcircuit 250 is in the first state, the fifth terminal D5 is connected to the first terminal D1 and disconnected from the third terminal D3, so that the first signal terminal X1 of the first transceiver subcircuit 210 is connected to the first electrode 110, and the fifth signal terminal X5 of the second transceiver subcircuit 240 is disconnected from the first electrode 110. The sixth terminal D6 is connected to the second terminal D2 and disconnected from the fourth terminal D4, so that the second signal terminal X2 of the first transceiver subcircuit 210 is connected to the second electrode 120, and the sixth signal terminal X6 of the second transceiver subcircuit 240 is disconnected from the second electrode 120.

In this way, when the switching subcircuit 250 is in the first state, the signal transceiver subcircuit as a capacitive coupling type HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of a capacitive coupling type HBC.

When the switching subcircuit 250 is in the second state, the fifth terminal D5 is connected to the third terminal D3 and disconnected from the first terminal D1, so that the first signal terminal X1 of the first transceiver subcircuit 210 is disconnected from the first electrode 110, and the fifth signal terminal X5 of the second transceiver subcircuit 240 is connected to the first electrode 110. The sixth terminal D6 is connected to the fourth terminal D4 and disconnected from the second terminal D2, so that the second signal terminal X2 of the first transceiver subcircuit 210 is disconnected from the second electrode 120, and the sixth signal terminal X6 of the second transceiver subcircuit 240 is connected to the second electrode 120.

In this way, when the switching subcircuit 250 is in the second state, the signal transceiver subcircuit as a current-coupled HBC is coupled to the first electrode 110 and the second electrode 120 respectively. At this time, the smart ring 100 can be a signal transceiver device of the current-coupled HBC.

In this embodiment, by switching the sub-circuit 250 , the smart ring 100 can support capacitive coupling HBC communication and current coupling HBC communication in different time periods, thereby improving the communication diversity of the smart ring 100 .

The voltage value corresponding to the electrostatic stress is very large, which can reach several thousand volts. When the electrostatic stress appears on the first electrode 110 and/or the second electrode 120 , the electrostatic stress with a large voltage can easily damage the electronic devices in the signal circuit 200 .

Therefore, in some examples, as shown in Fig. 19, the signal circuit 200 may further include an electrostatic discharge subcircuit 260. A first terminal of the electrostatic discharge subcircuit 260 is coupled to the first electrode 110, and a second terminal of the electrostatic discharge subcircuit 260 is coupled to the ground terminal GND.

When the first electrode 110 is subjected to electrostatic stress, the electrostatic discharge sub-circuit 260 can connect the first electrode 110 to the ground terminal GND and transmit the electrostatic stress to the ground terminal GND, thereby avoiding the transmission of electrostatic stress with a large pressure value to other electronic devices in the signal circuit 200, avoiding the electrostatic stress from damaging the electronic devices and causing failure of the electronic devices, and improving the reliability of the signal circuit and the wearable device.

19 , the signal circuit 200 may further include an electrostatic discharge subcircuit 260. A first terminal of the electrostatic discharge subcircuit 260 is coupled to the second electrode 120, and a second terminal of the electrostatic discharge subcircuit 260 is coupled to the ground terminal GND.

When the second electrode 120 is subjected to electrostatic stress, the electrostatic discharge sub-circuit 260 can connect the second electrode 120 to the ground terminal GND and transmit the electrostatic stress to the ground terminal GND, thereby avoiding the transmission of electrostatic stress with a large pressure value to other electronic devices in the signal circuit 200, avoiding damage to the electronic devices caused by electrostatic stress and causing failure of the electronic devices, and improving the reliability of the signal circuit and the wearable device.

Among them, when the smart ring 100 is used as a signal transceiver device of a capacitive coupling type HBC and the second electrode 120 is coupled to the ground terminal GND as a ground electrode, the electrostatic discharge sub-circuit 260 coupled to the second electrode 120 can be omitted, saving the cost of the signal circuit 200.

The electrostatic discharge subcircuit 260 may include a transient voltage suppressor (TVS) tube, or other suitable electronic devices, which is not limited in the present application.

Figure 20 shows a flow chart of a control method for a signal circuit provided in some embodiments of the present application; Figures 21 to 27 show different wearing scenarios of a smart ring on a human hand; Figure 28 shows a flow chart of a control method for a signal circuit provided in other embodiments of the present application.

The embodiment of the present application provides a control method for a signal circuit. After the smart ring 100 is worn on the user's finger, the method enables the compensation subcircuit 220 in the signal circuit 200 and the first capacitor C1 equivalent to the human skin and the second electrode 120 to form a parallel resonant network together, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit and the wearable device participate.

In some examples, the frequency of the signal received and sent in the first transceiver subcircuit 210 in the signal circuit 200 is fixed. As shown in FIG20 , taking the smart ring 100 as a receiving device in HBC communication and the signal circuit 200 for signal reception as an example, the control method of the signal circuit may include steps S310 to S380.

Step S310: the signal circuit obtains the wearing information of the smart ring 100.

The wearing information may be information indicating different wearing scenarios of the smart ring 100. The wearing information may be set by the user when initially wearing the smart ring, or may be determined by the smart ring 100 through its own sensors based on sensing data acquired by various sensors.

Exemplarily, different wearing information of the smart ring 100 may include wearing scenarios of multiple smart rings 100 as shown in Figures 21 to 27. The wearing information may include at least information indicating that the second electrode 120 in the smart ring 100 is not in contact with a finger as shown in Figure 21, information indicating that the second electrode 120 in the smart ring 100 is in contact with one finger as shown in Figures 22 to 25, and information indicating that the second electrode 120 in the smart ring 100 is in contact with two fingers as shown in Figures 26 and 27.

Step S320: the signal circuit determines the target parameter of the compensation sub-circuit 220 corresponding to the wearing information based on the wearing information.

The circuit structure of the compensation subcircuit 220 has been described in detail before, and will not be repeated here. In the case where the compensation subcircuit 220 includes an inductor, the target parameter may include an inductance value. In the case where the compensation subcircuit 220 includes both an inductor and a capacitor, the target parameter may include both an inductance value and a capacitance value.

For example, as shown in Fig. 10, when the compensation subcircuit 220 includes a first inductor L1, the target parameter may include the inductance value of the first inductor L1. As shown in Fig. 12, when the compensation subcircuit 220 includes an inductor component UL, the target parameter may include the inductance value of the inductor component UL.

For example, as shown in Fig. 13, when the compensation subcircuit 220 includes a second capacitor C2, the target parameter may include the capacitance value of the second capacitor C2. As shown in Fig. 14, when the compensation subcircuit 220 includes a capacitor component UC, the target parameter may include the capacitance value of the capacitor component UC.

For example, when the compensation subcircuit 220 includes both the inductor component UL and the capacitor component UC, the target parameter may include the inductance value of the inductor component UL and the capacitance value of the capacitor component UC. For ease of understanding, the following description will be made by taking the case where the compensation subcircuit 220 includes both the inductor component UL and the capacitor component UC as an example.

For each type of wearing information, the compensation subcircuit 220 can be pre-tested for signal transmission according to different parameters, and the parameters of the compensation subcircuit 220 with better signal transmission effect are used as the target parameters corresponding to the wearing information to establish a mapping relationship. After the wearing information is obtained, the target parameters of the compensation subcircuit 220 corresponding to each wearing information can be directly determined through the mapping relationship.

After determining the target parameters of the compensation subcircuit 220, the signal circuit 200 can use the controller to switch the states of the plurality of first switches K1 in the inductor component UL according to the target parameters, so that the inductance value of the inductor component UL is equal to the inductance value in the target parameters. Similarly, the controller can be used to switch the states of the plurality of second switches K2 in the capacitor component UC according to the target parameters, so that the capacitance value of the capacitor component UC is equal to the capacitance value in the target parameters.

Step S330: the signal circuit sends a notification to the sending device to enable the sending device to transmit the HBC signal.

After determining the target parameters, the smart ring 100 can send a notification to the sending device (e.g., a smart watch). After receiving the notification, the sending device transmits the HBC signal so that the HBC signal is transmitted to the smart ring (receiving device) 100 through the human body. The sending device may transmit the HBC signal multiple times. For example, the smart ring 100 notifies the sending device to transmit the HBC signal multiple times. For another example, the smart ring 100 notifies once, and the sending device transmits multiple HBC signals.

There are many ways for the smart ring 100 to send notifications to the sending device. For example, the smart ring 100 can use human skin to send HBC signals to send notifications to the sending device. For another example, the smart ring 100 and the sending device can simultaneously support other communication methods (such as Bluetooth, near field communication (NFC) and other suitable communication methods), and the smart ring 100 sends notifications to the sending device by sending NFC signals.

Step S340: when the signal circuit 200 receives the HBC signal transmitted by the transmitting device, a judgment result is obtained as to whether the signal strength received by the signal circuit 200 is greater than a preset strength threshold.

The smart ring 100 can perform Bluetooth communication with the sending device to determine whether the sending device has sent the HBC signal. Alternatively, the smart ring 100 can also determine whether the sending device has sent the HBC signal by the signal strength received by the first transceiver subcircuit 110. Of course, the smart ring 100 can also determine whether the sending device has sent the HBC signal by other means.

When the smart ring 100 determines that the sending device has sent the HBC signal, it obtains a judgment result of whether the signal strength received by the signal circuit 200 is greater than a preset strength threshold.

If the judgment result indicates that the signal strength received by the signal circuit 200 of the current parameters is greater than the preset strength threshold, the smart ring 100 believes that the compensation subcircuit 220 has a better reception effect of receiving the HBC signal according to the current parameters. Step S350 is executed: the signal circuit 200 uses the current parameters of the compensation subcircuit 220 as the target parameters.

If the judgment result indicates that the signal strength received by the signal circuit 200 with the current parameters is less than or equal to the preset strength threshold, the smart ring 100 considers that the receiving effect of the compensation subcircuit 220 receiving the HBC signal with the current parameters is poor, and will not use the current parameters of the compensation subcircuit 220 as the target parameters. Step S360 is executed: the signal circuit 200 changes the parameters of the compensation subcircuit 220.

Exemplarily, the signal circuit 200 changes the parameters of the compensation subcircuit 220, which may be that the signal circuit 200 changes the inductance value of the compensation subcircuit 220. For example, when the compensation subcircuit 220 includes an inductor component, step S360 may include the signal circuit 200 changing the inductance value of the inductor component. For another example, when the compensation subcircuit 220 includes both an inductor component and a capacitor component, the signal circuit 200 may change the inductance value of the inductor component in the compensation subcircuit 220, and change the capacitance value of the capacitor component in the compensation subcircuit 220.

In step S360, the signal circuit 200 changes the parameters of the compensation subcircuit 220 each time, so that the parameters after the change are different from the previous parameters. After completing step S360, step S370 can be performed: determining whether the compensation subcircuit 220 has traversed the detection results of all parameters of the compensation subcircuit 220.

If the detection result indicates that the compensation subcircuit 220 has not traversed all the parameters of the compensation subcircuit 220, the process returns to step S340, and the signal circuit 200 receives the HBC signal transmitted by the transmitting device according to the parameters changed by the compensation subcircuit 220. After the signal circuit 200 receives the HBC signal, the signal strength of the HBC signal received by the signal circuit 200 is obtained.

As can be known from the previous process, if the compensation subcircuit 220 receives the HBC signal with poor reception effect with the current parameters, the parameters will be changed in step S360. If the HBC signal reception effect is poor for multiple times, all parameters of the compensation subcircuit 220 can be traversed in step S360.

When the detection result indicates that the compensation sub-circuit 220 has not traversed all the detection results of the parameters of the compensation sub-circuit 220 , returning to step S340 can help find parameters that can have a better reception effect on the HBC signal.

In the case where the detection result indicates that the compensation subcircuit 220 has traversed all the detection results of the parameters of the compensation subcircuit 220, it can be considered that no matter what parameters the compensation subcircuit 220 has, the compensation subcircuit 220 cannot have a better reception effect on the HBC signal. In this way, step S380 can be performed: the signal circuit 200 determines the parameters of the compensation subcircuit 220 corresponding to the highest signal strength as the target parameters.

Exemplarily, after traversing the parameters of all compensation subcircuits 220 to receive HBC signals, the compensation subcircuit 220 obtains the signal strengths of the HBC signals received by the multiple signal circuits, and determines the target signal strength with the highest signal strength from the signal strengths of the multiple HBC signals.

The parameters set for the HBC signal reception are determined as target parameters according to the target signal strength.

It should be noted that the process shown in FIG. 20 is described by taking the example of executing step S370 after step S340. In some other exemplary processes, as shown in FIG. 28, step S370 may be executed first, and step S340 may be executed again when the detection result in step S370 indicates that the compensation subcircuit 220 has not traversed the detection results of all parameters of the compensation subcircuit 220. After step S360 is executed, the process returns to execute step S370.

In this example, when the signal frequency received and transmitted by the first transceiver sub-circuit 210 remains fixed, the parameters of the compensation sub-circuit 220 can be traversed so that the signal circuit 200 receives the HBC signal with better or optimal strength, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

Furthermore, the above steps S310 to S380 can be considered to be executed after the smart ring 100 is worn on the user's finger for the first time, or can be considered to be executed after each change of the wearing information of the smart ring 100. For example, the user changes the wearing finger of the smart ring 100, so that the wearing scenario of the smart ring 100 changes from the second electrode 120 contacting one finger to the second electrode 120 contacting two fingers. At this time, steps S310 to S380 can be executed to optimize the parameters of the compensation subcircuit 220 and improve the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

FIG. 29 shows a flow chart of a signal circuit control method provided in some other embodiments of the present application.

In some examples, the frequency of the signal received and transmitted by the first transceiver subcircuit 210 in the signal circuit 200 is adjustable. As shown in FIG29 , taking the smart ring 100 as a receiving device in HBC communication and the signal circuit 200 for signal reception as an example, the control method of the signal circuit may include steps S410 to S470.

Step S410: the signal circuit obtains the wearing information of the smart ring 100.

The wearing information may be set by the user when initially wearing the smart ring 100, and may be information indicating different wearing conditions of the smart ring 100. The wearing information may also be determined by the smart ring 100 through its own sensors based on sensing data acquired by various sensors.

Exemplarily, different wearing conditions of the smart ring 100 may include wearing information indicating multiple smart rings 100 as shown in Figures 21 to 27. The wearing information may include at least information indicating that the second electrode 120 in the smart ring 100 as shown in Figure 21 is not in contact with a finger, information indicating that the second electrode 120 in the smart ring 100 as shown in Figures 22 to 25 is in contact with one finger, and information indicating that the second electrode 120 in the smart ring 100 as shown in Figures 26 and 27 is in contact with two fingers.

Step S420: The signal circuit determines a target frequency range based on the wearing information.

The human body communication frequency may be within a frequency range greater than or equal to 10 kHz and less than or equal to 100 MHz.

For each type of wearing information, the compensation subcircuit 220 can be pre-tested for signal transmission according to multiple different frequency intervals in the human body communication frequency range, and the frequency interval with better signal transmission effect is used as the target frequency interval corresponding to the wearing information to establish a mapping relationship. After the wearing information is obtained, the target frequency interval of the compensation subcircuit 220 corresponding to each wearing information can be directly determined through the mapping relationship.

After the wearing information of the smart ring 100 is determined, the controller can be used to adjust the human body communication frequency to the corresponding target frequency range.

Step S430: the signal circuit sends a notification to the sending device so that the sending device transmits the HBC signal according to the target frequency interval.

After determining the target parameters, the smart ring 100 can send a notification to the sending device (e.g., a smart watch) through HBC to communicate in the target frequency range. After receiving the notification, the sending device transmits the HBC signal so that the HBC signal is transmitted to the smart ring (receiving device) 100 through the human body. The sending device will transmit the HBC signal multiple times. For example, the smart ring 100 notifies the sending device to transmit the HBC signal multiple times. For another example, the smart ring 100 notifies once, and the sending device transmits multiple HBC signals.

The signal frequencies of the HBC signals transmitted by the sending device are all within the target frequency range.

Step S440: the signal circuit scans the HBC signal within the target frequency range to obtain the signal strength of the HBC signal at each frequency.

The smart ring 100 can perform Bluetooth communication with the sending device to determine whether the sending device has sent the HBC signal. Alternatively, the smart ring 100 can also determine whether the sending device has sent the HBC signal by the signal strength received by the first transceiver subcircuit. Of course, the smart ring 100 can also determine whether the sending device has sent the HBC signal by other means.

When determining that the sending device has sent HBC signals of various frequencies, the smart ring 100 records the signal strength of the HBC signal of each frequency received by the signal circuit during the frequency scanning process.

Step S450: When the signal circuit receives HBC signals of multiple frequencies, the signal circuit obtains a detection result of whether the signal strength of at least one HBC is greater than a strength threshold.

When the detection result indicates that the signal strength of at least one HBC signal received by the signal circuit 200 is greater than the preset strength threshold, the smart ring 100 considers that the signal circuit has a better reception effect of receiving the HBC signal at the corresponding target frequency. The target frequency refers to the communication frequency corresponding to the signal strength greater than the preset strength threshold.

Therefore, when the detection result indicates that the strength of at least one signal received by the signal circuit is greater than the preset strength threshold, step S460 is executed: the signal circuit uses the target frequency as the human body communication frequency of the smart ring 100 .

In this way, the signal circuit can determine the target frequency interval of the signal that matches the user's current wearing posture and has a better communication effect based on the wearing information of the wearable device, and then determine the human body communication frequency in the target frequency interval, which can improve the efficiency of the signal circuit in determining the HBC signal frequency.

When the detection result indicates that the signal strength of the HBC signal received by the compensation subcircuit 220 of the current parameters is less than or equal to the preset strength threshold, the smart ring 100 believes that the signal circuit has a poor reception effect of receiving the HBC signal in the target frequency range, and the parameters of the compensation subcircuit 220 in the signal circuit need to be further adjusted. Therefore, step S470 is executed: the signal circuit adjusts the parameters of the compensation subcircuit 220.

How to adjust the parameters of the compensation sub-circuit 220 in the specific step S470 is basically the same as the method of adjusting the compensation sub-circuit 220 in the above-mentioned signal circuit 200 in which the signal frequency received and transmitted by the first transceiver sub-circuit 210 is fixed, and will not be repeated here.

It should be noted that the process shown in FIG. 29 is described by first adjusting the human body communication frequency of the signal circuit and then adjusting the compensation parameters of the compensation subcircuit in the signal circuit. In some other example processes, the compensation parameters of the compensation subcircuit in the signal circuit may be adjusted first and then the human body communication frequency of the signal circuit may be adjusted. The embodiments of the present application do not limit the control order of the human body communication frequency and the compensation parameters of the compensation subcircuit 220.

By adjusting the parameters of the compensation sub-circuit 220 , the parameters of the compensation sub-circuit 220 can be adjusted so that the signal circuit 200 receives a better or optimal HBC signal strength.

In this example, when the signal frequency received and transmitted by the first transceiver sub-circuit 210 is adjustable, the signal frequency received and transmitted by the first transceiver sub-circuit 210 and the parameters of the traversal compensation sub-circuit 220 can be adjusted so that the signal circuit 200 receives the HBC signal with better or optimal strength, thereby improving the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

Furthermore, the above steps S410 to S470 can be considered to be executed after the smart ring 100 is worn on the user's finger for the first time, or can be considered to be executed after each change of the wearing information of the smart ring 100. For example, the user changes the wearing finger of the smart ring 100, so that the wearing scenario of the smart ring 100 changes from the second electrode 120 contacting one finger to the second electrode 120 contacting two fingers. At this time, steps S410 to S470 can be executed to optimize the parameters of the compensation subcircuit 220 and improve the reliability of HBC signal transmission in the HBC communication system in which the signal circuit 200 and the wearable device 100 participate.

The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims (20)

1. A wearable device, comprising:

a first electrode for coupling with human skin;

the second electrode is arranged at intervals with the first electrode;

an insulator between the first electrode and the second electrode to insulate the first electrode and the second electrode from each other;

A circuit board positioned between the first electrode and the second electrode, a first connection point of the circuit board being coupled with the first electrode, a second connection point of the circuit board being coupled with the second electrode;

the wearable device transmits signals to the human skin at least by using the first electrode and/or receives signals transmitted by the human skin.

2. The wearable device of claim 1, wherein the first electrode comprises a first arcuate surface and the second electrode comprises a second arcuate surface;

The angle of the central angle corresponding to the second arc-shaped surface is larger than that of the central angle corresponding to the first arc-shaped surface.

3. The wearable device of claim 1 or 2, wherein the second electrode acts as a housing of the wearable device; the shell is provided with an accommodating space;

the insulator is at least partially located in the accommodation space.

4. A wearable device according to claim 3, wherein the circuit board is located within the receiving space, the circuit board being located on a side of the insulator remote from the first electrode;

The wearable device further includes a conductive structure having one end coupled to the first connection point of the circuit board and the other end coupled to the first electrode through the insulator.

5. The wearable device of any of claims 1-4, wherein the insulator comprises a flexible material.

6. The wearable device of any of claims 1-5, wherein the wearable device comprises a ring or a finger ring.

7. A signal circuit, characterized by being applied to a wearable device, the wearable device further comprising a first electrode and a second electrode; the first electrode is used for sending signals to human skin and/or receiving signals transmitted by the human skin;

The signal circuit includes:

The first transceiver sub-circuit comprises a first signal end and a second signal end; the first signal end is used for being coupled with the first electrode; the second signal terminal is used for being coupled with the second electrode and the grounding terminal at the same time;

the compensation sub-circuit comprises a third signal end and a fourth signal end; the third signal terminal is used for being coupled with the first electrode, and the fourth signal terminal is used for being coupled with the second electrode.

8. The signal circuit of claim 7, wherein the second electrode is equivalent to form a first capacitor with human skin when the second electrode is coupled with human skin;

The compensation subcircuit is configured to form a parallel resonant network with the first capacitor.

9. The signal circuit of claim 7 or 8, wherein the compensation subcircuit comprises a first inductor; a first end of the first inductor is used for being coupled with the first electrode, and a second end of the first inductor is used for being coupled with the second electrode;

The first inductor includes a fixed value inductor or an adjustable inductor.

10. The signal circuit of claim 7 or 8, wherein the compensation subcircuit comprises an inductor assembly having a first end for coupling with the first electrode and a second end for coupling with the second electrode;

the inductor assembly includes a plurality of inductor units connected in series with each other; each of the inductor units includes a first switch and a second inductor connected in parallel with each other.

11. The signal circuit of claim 9 or 10, wherein the compensation subcircuit further comprises a second capacitor; a first plate of the second capacitor is used for being coupled with the first electrode, and a second plate of the second capacitor is used for being coupled with the second electrode;

The second capacitor includes a fixed value capacitor or an adjustable capacitor.

12. The signal circuit of claim 9 or 10, wherein the compensation subcircuit further comprises a capacitor assembly; the capacitor assembly includes a plurality of capacitor cells connected in parallel with each other; a first end of each of the capacitor units is used for being coupled with the first electrode, and a second end of each of the capacitor units is used for being coupled with the second electrode;

Each of the capacitor units includes a second switch and a third capacitor connected in series with each other.

13. The signal circuit according to any one of claims 7-12, wherein the signal circuit further comprises a compensation switching sub-circuit; the compensation switching sub-circuit is connected in series with the compensation sub-circuit.

14. The signal circuit according to any one of claims 7 to 13, wherein the signal circuit further comprises:

the second transceiver sub-circuit comprises a fifth signal end and a sixth signal end;

A switching sub-circuit coupled to the first signal terminal, the second signal terminal, the fifth signal terminal, and the sixth signal terminal, respectively; and is further configured to couple to the first electrode and the second electrode;

The first electrode is connected with the first signal end and disconnected with the fifth signal end, and the second electrode is connected with the second signal end and disconnected with the sixth signal end under the condition that the switching sub-circuit is in a first state;

and under the condition that the switching sub-circuit is in a second state, the first electrode is connected with the fifth signal end and disconnected with the first signal end, and the second electrode is connected with the sixth signal end and disconnected with the second signal end.

15. A control method of a signal circuit, characterized by being applied to the signal circuit according to any one of claims 7 to 14; the method comprises the following steps:

in the case that the second electrode is coupled with the skin of the human body to form a first capacitor equivalently, the signal circuit and the first capacitor form a parallel resonance network together through a compensation sub-circuit.

16. The method of claim 15, wherein the compensation subcircuit includes the inductor assembly;

the signal circuit and the first capacitor together form a parallel resonance network through a compensation sub-circuit, and the parallel resonance network comprises:

the signal circuit controls the on or off of at least one first switch to change the inductance value of the inductor assembly so that the inductor assembly with the changed inductance value and the first capacitor form a parallel resonance network together;

Or alternatively

The compensation subcircuit includes a first inductor including an adjustable inductor;

the signal circuit and the first capacitor together form a parallel resonance network through a compensation sub-circuit, and the parallel resonance network comprises:

The signal circuit adjusts the inductance value of the first inductor so that the first inductor and the first capacitor after the inductance value is changed form a parallel resonance network together.

17. The method of claim 16, wherein the compensation subcircuit further comprises the capacitor assembly;

The signal circuit and the first capacitor together form a parallel resonance network through a compensation sub-circuit, and the parallel resonance network further comprises:

The signal circuit controls the closing or opening of at least one second switch, changes the capacitance value of the capacitor assembly, and adjusts the parallel capacitance value of the first capacitor and the capacitor assembly in the parallel resonance network;

Or alternatively

The compensation subcircuit includes a second capacitor, the first inductor including an adjustable capacitor;

The signal circuit and the first capacitor together form a parallel resonance network through a compensation sub-circuit, and the parallel resonance network further comprises:

The signal circuit adjusts a capacitance value of the second capacitor to adjust a parallel capacitance value of the first capacitor and the second capacitor in the parallel resonant network.

18. The method according to any one of claims 15-17, further comprising:

The signal circuit acquires wearing information of the wearable equipment;

the signal circuit determines a target frequency interval based on wearing information;

The signal circuit informs the opposite side equipment to communicate according to the target frequency interval;

The signal circuit scans signals in the target frequency interval, and takes the target frequency with the signal strength larger than a preset strength threshold value as the human body communication frequency of the signal circuit; wherein the target frequency is a frequency in the target frequency interval.

19. A circuit board, characterized by being applied to the wearable device of any of claims 1-6; the circuit board comprising a signal circuit as claimed in any one of claims 7-14.

20. A human body communication system, characterized by comprising a transmitting device and a receiving device that communicate with each other;

the transmitting device comprising the wearable device of any of claims 1-6; and/or the number of the groups of groups,

The receiving device comprising a wearable device as claimed in any of claims 1-6.