JP2022000991A - Remote antenna switching system - Google Patents

Abstract

To provide a system in which a configuration of an antenna switching receiving device is simple and a desired antenna switching can be performed reliably in a remote antenna switching system for connecting between an antenna switching transmitter and an antenna switching receiver with multiple antennas connected with a single coaxial cable.SOLUTION: A first antenna switching transmitter 10a superimposes an encoded tri-level signal onto an RF signal to be an L signal when a clock signal is 0, an M signal when the clock signal is 1 and a data signal is 0, and an H signal when the data signal is 1, based on the clock and data signals for selecting an antenna. A first antenna-switching receiver 20a decodes the superimposed tri-level signal and selects and connects a designated antenna.SELECTED DRAWING: Figure 1

Description

The present invention relates to a remote antenna switching system in which an antenna switching transmitting device and an antenna switching receiving device connected to a plurality of antennas are connected by a single coaxial cable.

A system for transmitting a transmission / reception signal and an antenna switching signal with a single coaxial cable by superimposing an antenna switching signal on the transmission / reception signal has been conventionally known.

In Patent Document 1 (Japanese Unexamined Patent Publication No. 2008-244569), the control unit of the reader superimposes a control signal for antenna switching on a high frequency signal output from the high frequency circuit to the antenna unit. The antenna unit includes an RFID having a separation means for separating the superposed signal into a high frequency signal and a control signal, a switch circuit for switching the loop antenna, and a control circuit for controlling the switch circuit based on the control signal separated by the separation means. A tag reader is described.

In Patent Document 2 (Japanese Unexamined Patent Publication No. 2002-344228), when there are a plurality of coaxial excitation type monopole antennas, a high frequency signal switch for selecting the antenna is provided for each of the plurality of antennas, and the switching signal is used. , It is described that it is generated by a pulse count type signal superimposed on a high frequency signal output from the interrogator.

Further, in a system in which an antenna switching signal is superimposed on a transmission / reception signal and transmitted, it is conceivable to use a clock signal and a data signal as the antenna switching signal and transmit the clock signal and the data signal as a ternary signal. A method of generating a ternary signal from a clock signal and a data signal has also been conventionally known.

In Patent Document 3 (Japanese Unexamined Patent Publication No. 2016-82339), when the logical value of the data signal is 1 and the logical value of the clock signal is 0, a signal having a logical value of 1 is output. Further, the signal generation circuit outputs a signal having a logic value of -1 when the logic value of the data signal is 0 and the logic value of the clock signal is 0. Further, as the signal generation circuit, a signal generation circuit that outputs a signal having a logic value of 0 when the logic value of the data signal is 0 or 1 and the logic value of the clock signal is 1 is described.

Japanese Unexamined Patent Publication No. 2008-2445669 Japanese Unexamined Patent Publication No. 2002-344228 Japanese Unexamined Patent Publication No. 2016-8239

In the RFID tag reader described in Patent Document 1, an example of a control signal composed of two values of 1 or 0 is described as a digitization control signal in FIG. When transmitting control data using a binary signal, for example, a preamble and a data body are provided, and complicated processing such as decoding the control signal for antenna switching after receiving the preamble is required. There is a problem that it becomes complicated.

The article management system described in Patent Document 2 is composed of a 4-bit binary counter, and only a clock signal is input to the switching signal generation circuit (see FIGS. 10-11). In this case, there is a possibility that a malfunction may occur due to chattering of the clock signal or the like, and it is necessary to add a chattering prevention circuit. Therefore, there is still a problem that the configuration of the antenna switching receiving device becomes complicated.

In the signal generation circuit of Patent Document 3, it is described that a data signal and a clock signal are converted into a ternary signal. Specifically, when the logical value of the data signal is 1 and the logical value of the clock signal is 0, a signal having a logical value of 1 is output, and the logical value of the data signal is 0 and the logical value of the clock signal is 0. When the logical value is 0, a signal with a logical value of -1 is output, and when the logical value of the data signal is 0 or 1, and the logical value of the clock signal is 1, the signal with the logical value of 0 is output. Is output (see claim 1).
However, when the ternary signal is generated by the above method, the clock signal and the data signal are separated from the ternary signal by a simple circuit because the relationship between the clock signal and the ternary signal changes depending on the logical value of the data signal. There is a problem that it is difficult to do.

A main object of the present invention is a remote antenna switching system in which an antenna switching transmitter and an antenna switching receiver connected to a plurality of antennas are connected by a single coaxial cable, and the configuration of the antenna switching receiver is simple. Further, it is an object of the present invention to provide a system capable of reliably performing desired antenna switching.

(1)
The remote antenna switching system according to one aspect is a remote antenna switching system composed of an antenna switching transmitter and an antenna switching receiver.
Multiple antennas are connected to the antenna switching receiver, the antenna switching transmitter and the antenna switching receiver are connected by one coaxial line, and the antenna switching transmitter superimposes the transmitted RF signal on the stepped DC voltage. The signal or RF signal is transmitted with a stepped amplitude, and the antenna switching receiver selects one antenna specified from multiple antennas based on the stepped DC voltage or stepped amplitude. The signal to select and connect and select one antenna is composed of a binary clock signal and a binary data signal, and the DC voltage or amplitude is composed of the first signal, the second signal, and the third signal. The first signal has the largest DC voltage or amplitude, the third signal has the smallest DC voltage or amplitude, and the second signal has the smallest DC voltage or amplitude than the first signal. , And if the clock signal is set to be larger than the third signal and the clock signal is one of the two values, the third signal is selected, and if the clock signal is the other of the two values, the data signal is one of the two values. If so, the first signal is selected, and if the data signal is the other of the two values, the second signal is selected.

In this case, the decoder circuit of the antenna switching receiver can be configured by two comparators and a D flip-flop that captures a data signal at the timing when the clock signal changes from one to the other. As a result, the configuration of the antenna switching receiving device can be easily and surely performed as desired.

(2)
The remote antenna switching system according to the second invention is a remote antenna switching system according to one aspect, wherein the antenna switching transmitter includes an encoder circuit and a DC voltage generation circuit, and the encoder circuit is used as a clock signal and a data signal. The corresponding ternary signal may be generated, and the DC voltage generation circuit may generate the DC voltage corresponding to the ternary signal.

In this case, with a simple configuration, it is possible to generate an RF signal having a ternary DC voltage corresponding to the clock signal and the data signal.

(3)
The remote antenna switching system according to the third invention is a remote antenna switching system according to one aspect, wherein the antenna switching transmitter includes an encoder circuit and an amplitude control circuit, and the encoder circuit corresponds to a clock signal and a data signal. The ternary signal may be generated, and the amplitude control circuit may control the amplitude of the RF signal to have an amplitude corresponding to the ternary signal.

In this case, with a simple configuration, it is possible to generate an RF signal having a ternary amplitude corresponding to the clock signal and the data signal.

(4)
In the remote antenna switching system according to the fourth aspect of the invention, in the remote antenna switching system according to the third aspect to the third aspect, the antenna switching receiving device includes a constant voltage circuit, a decoder circuit, and a switch circuit.
The constant voltage circuit generates a constant voltage from the DC voltage of the input RF signal, the decoder circuit separates the clock signal and the data signal from the DC voltage of the RF signal, and further, the clock signal and the data signal are D flip-flops. The switch circuit may conduct a switch with an antenna to be connected based on the antenna selection signal.

In this case, the antenna switching receiver has a simple configuration and is stepped by connecting to the antenna switching transmitter that outputs a signal obtained by superimposing the RF signal to be transmitted on the stepped DC voltage with a single coaxial cable. A specified antenna can be selected and connected from a plurality of antennas based on the DC voltage.

(5)
The remote antenna switching system according to the fifth aspect of the present invention is the remote antenna switching system according to the fourth aspect of the invention, wherein the antenna switching receiving device includes a detection circuit, a constant voltage circuit, a decoder circuit, and a switch circuit. including.
The detection circuit converts the input RF signal into a DC voltage, the constant voltage circuit generates a constant voltage from the DC voltage, the decoder circuit separates the clock signal and the data signal from the DC voltage, and further, the clock signal. And the data signal is input to the D flip flop to generate an antenna selection signal, and the switch circuit may conduct the switch with the antenna to be connected based on the antenna selection signal.

In this case, the antenna switching receiver is connected to the antenna switching transmitter that outputs a signal in which the amplitude of the RF signal to be transmitted is stepped by a single coaxial cable, so that the amplitude can be stepped with a simple configuration. Based on this, it is possible to select and connect a specified antenna from a plurality of antennas.

(6)
The remote antenna switching system according to the sixth invention may input the separated clock signal to the clock input terminal of the D flip-flop via the delay circuit in the remote antenna switching system according to the fourth or fifth invention. good.

In this case, it is possible to prevent the D flip-flop from malfunctioning even when, for example, a stepped DC voltage or a stepped amplitude rising or falling speed is slow.

(7)
In the remote antenna switching system according to the seventh invention, in the remote antenna switching system according to the second to fifth inventions, the antenna switching transmitter may further include a short circuit detection circuit.

In this case, even in the antenna switching transmitter that outputs a signal in which the RF signal to be transmitted is superimposed on the stepped DC voltage, by controlling so that the DC voltage is not superimposed when a short circuit is detected, an accident due to an excessive current can occur. Can be prevented.

(8)
The remote antenna switching system according to the eighth aspect of the invention is the remote antenna switching system according to the sixth aspect from the first aspect. It may be constant.

In this case, since the DC voltage and amplitude of the RF signal during transmission / reception of the RF signal are constant, it is possible to prevent performance deterioration during transmission / reception due to the adoption of this remote antenna switching system.

It is a block diagram which shows the structure of the remote antenna switching system in 1st Embodiment. It is a table which shows the correspondence between a data, a clock input and a ternary signal. It is a circuit diagram which shows an example of a decoder circuit. It is an example of the operation waveform of the decoder circuit of FIG. It is a figure which shows an example of the DC voltage of the RF signal input and the operation of a decoder circuit in 1st Embodiment. It is a block diagram which shows the structure of the remote antenna switching system in 2nd Embodiment. It is a circuit diagram which shows an example of the detection circuit in 2nd Embodiment. It is a figure which shows an example of the waveform of RF signal input and the operation of a decoder circuit in 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Further, in the case of the same reference numeral, their names and functions are also the same. Therefore, detailed explanations about them will not be repeated.

[First Embodiment]
FIG. 1 is a block diagram showing the configuration of the first remote antenna switching system 40a in the first embodiment, and FIG. 2 is a table showing the correspondence between data, clock input and a ternary signal.

(Configuration of the first remote antenna switching system 40a)
The first remote antenna switching system 40a is composed of a first antenna switching transmitting device 10a and a first antenna switching receiving device 20a. The first antenna switching transmitter 10a and the first antenna switching receiver 20a are connected by one coaxial cable 30, and the first antenna switching receiver 20a has a plurality of antennas (ANT1-ANT4). Be connected.

The first antenna switching transmitter 10a includes a DC voltage generation circuit 11, an encoder circuit 12, and a short circuit detection circuit 13. The encoder circuit 12 receives data and clock input, and generates a ternary signal (H, M, L) according to the correspondence table of FIG.
The DC voltage generation circuit 11 receives the ternary signal of the encoder circuit 12 and generates a DC voltage corresponding to the ternary signal. In the case of this embodiment, for example, the H signal is 5V, the M signal is 2.5V, and the L signal is 0V.

The short-circuit detection circuit 13 compares the set value of the output voltage of the DC voltage generation circuit 11 with the actual DC voltage of the first antenna switching transmitter 10a, and the difference between the set value and the actual DC voltage is large. In that case, it is determined that the circuit is short-circuited, and the voltage is fed back to the DC voltage generation circuit 11.
The short-circuit detection circuit 13 may not be included in the first antenna switching transmitter 10a, but it is desirable that the short-circuit detection circuit 13 be included in order to prevent an accident due to an excessive current.

The first antenna switching receiver 20a is composed of a constant voltage circuit 21, a decoder circuit 22, and a switch circuit 23. The constant voltage circuit 21 receives the DC component of the RF signal input and generates a constant voltage used as a power source for the decoder circuit 22 and the switch circuit 23. The decoder circuit 22 will be described later. The switch circuit 23 receives the antenna selection signal of the decoder circuit 22 and conducts the switch connecting the selected antenna and the RF signal input.

(Configuration and operation of decoder circuit 22)
FIG. 3 is a circuit diagram showing an example of the decoder circuit 22 according to the first embodiment. Further, FIG. 4 is a diagram showing an example of the operating waveform of the decoder circuit 22 of FIG.

The decoder circuit 22 is composed of two comparators (U1, U2), two D flip-flops (A3, A4), a delay circuit (A1, A2), and an antenna decoding logic (A5-A8).
The output of the comparator (U1) is connected to the D input of the D flip-flop (A3), and the output of the comparator (U2) is connected to the two D flip-flops (A3, A4) via the delay circuits (A1, A2). It is connected to the clock (CLK) input of.
The Q output of the D flip-flop (A3) is connected to the D input of the D flip-flop (A4). The outputs of the two D flip-flops (A3, A4) are input to the antenna decoding logic (A5-A8).

The comparator (U1) compares the voltage of the input (INPUT) with the reference voltage (V2), sets the output (D) to 1 when it is higher than the reference voltage (V2), and sets it to 0 when it is lower.
The comparator (U2) compares the voltage of the input (INPUT) with the reference voltage (V3), sets the output (CLK) to 1 when it is higher than the reference voltage (V3), and sets it to 0 when it is lower.
The delay circuits (A1 and A2) are inserted so that the D input of the D flip-flop is switched before the CLK input even when the voltage rise of the input (INPUT) is slow. In the embodiment of FIGS. 3 and 4, the input (INPUT) is 5V for the H signal, 2.5V for the M signal, and 0V for the L signal, V2 is 3.5V, and V3 is 1.5V. Is.

As shown in FIG. 4, in the operation waveform of the decoder circuit 22, the data (D) changes from 0-0-1-1-1-0-0 at the rising edge of the clock (CLK), and at this time (Q1, Q2) changes as (0, *)-(0,0)-(1,0)-(1,1)-(0,1)-(0,0).
Then, with the above change of (Q1, Q2), the output of the antenna decoding logic (A5-A8) is (*)-(ANT1 selection)-(ANT3 selection)-(ANT4 selection)-(ANT2 selection)-. It is switched to (ANT1 selection), and it is shown that any of the four antennas can be selected by the decoder circuit 22 in FIG. Note that * indicates that the data at that location is indefinite.

FIG. 5 is a diagram showing an example of the DC voltage of the RF signal input and the operation of the decoder circuit in the first embodiment. That is, it is an example of an operation waveform for showing a more practical operation of the first remote antenna switching system 40a.

As shown in FIG. 5, in the first remote antenna switching system 40a, two clock signals are inserted at the time of transmitting the antenna switching signal, and the first antenna switching transmission is performed corresponding to the data signals at the rising edge of the two clock signals. The DC voltage of the RF signal output of the device 10a changes stepwise.
In the first antenna switching receiving device 20a, one of the first antenna and the fourth antenna is selected by the decoder circuit 22 according to the value of the data signal at the rising edge of the two clock signals.
When the RF signal is transmitted and received after the antenna switching signal transmission is completed, the DC component of the input signal is fixed to a voltage corresponding to the H signal of the ternary signal, for example, 5V.
In this embodiment, the number of D flip-flops is 2, and the number of antennas that can be switched is 4, but when the number of D flip-flops is n, the number of antennas that can be switched is 2. It becomes the nth power of.

[Second Embodiment]
FIG. 6 is a block diagram showing the configuration of the second remote antenna switching system 40b in the second embodiment, and FIG. 7 is a circuit diagram of the detection circuit 24 included in the second remote antenna switching system 40b. ..

(Configuration of the second remote antenna switching system 40b)
The second remote antenna switching system 40b includes a second antenna switching transmitting device 10b and a second antenna switching receiving device 20b.
The second antenna switching transmitter 10b and the second antenna switching receiver 20b are connected by one coaxial cable 30, and the second antenna switching receiver 20b has a plurality of antennas (ANT1-ANT4). Be connected.

The second antenna switching transmitter 10b includes an amplitude control circuit 14 and an encoder circuit 12. The encoder circuit 12 is the same as the encoder circuit 12 of the first embodiment. The amplitude control circuit 14 receives the ternary signal of the encoder circuit 12 and controls the amplitude of the RF signal so that the amplitude corresponds to the ternary signal. In the case of the second embodiment, for example, the H signal is 5 Vp-p, the M signal is 2.5 Vp-p, and the L signal is 0 Vp-p.

The second antenna switching receiver 20b is composed of a constant voltage circuit 21, a detection circuit 24, a decoder circuit 22, and a switch circuit 23. The detection circuit 24 detects both waves of the RF input signal and sends the DC voltage of the output to the constant voltage circuit 21 and the decoder circuit 22.
The operation of the constant voltage circuit 21, the decoder circuit 22, and the switch circuit 23 is the same as that of the first embodiment.

FIG. 7 is a diagram showing an example of the circuit of the detection circuit 24.
The detection circuit 24 shown in FIG. 7 is a double-wave detection circuit. When the RF signal is input from the input terminal 24a, the detection circuit 24 outputs a DC voltage close to the amplitude of the RF signal from the output terminal 24b.

FIG. 8 is a diagram showing an example of an operation waveform for showing a more practical operation of the second remote antenna switching system 40b.

As shown in FIG. 8, in the second remote antenna switching system 40b, two clock signals and a data signal are inserted at the time of transmitting the antenna switching signal, and the second antenna switching corresponds to the two clock signals and the data signal. The amplitude of the RF signal output of the transmitter 10b changes stepwise.
In the second antenna switching receiver 20b, the detection circuit 24 outputs a DC voltage corresponding to the amplitude of the RF signal input.
Next, the decoder circuit 22 selects one of the first antenna and the fourth antenna according to the value of the data signal at the rising edge of the two clock signals.
In the case of RF signal transmission after the antenna switching signal transmission is completed, the amplitude of the RF signal is fixed to the amplitude corresponding to the H signal of the ternary signal. (In the case of receiving the RF signal, the RF signal is not transmitted from the second antenna switching transmitter 10b.)
In this embodiment, the number of D flip-flops is 2, and the number of antennas that can be switched is 4, but when the number of D flip-flops is n, the number of antennas that can be switched is 2. It becomes the nth power of.

In the present invention, the first antenna switching transmitter 10a and the second antenna switching transmitter 10b correspond to the "antenna switching transmitter", and the first antenna switching receiver 20a and the second antenna switching receiver 20b Corresponds to the "antenna switching receiver", the H signal corresponds to the "first signal", the M signal corresponds to the "second signal", the L signal corresponds to the "third signal", and DC voltage is generated. The circuit 11 corresponds to the "DC voltage generation circuit", the encoder circuit 12 corresponds to the "encoder circuit", the short circuit detection circuit 13 corresponds to the "short circuit detection circuit", and the amplitude control circuit 14 corresponds to the "amplification control circuit". The constant voltage circuit 21 corresponds to the "constant voltage circuit", the decoder circuit 22 corresponds to the "decoder circuit", the switch circuit 23 corresponds to the "switch circuit", and the detection circuit 24 corresponds to the "detection circuit". Correspondingly, the coaxial cable 30 corresponds to the "coaxial cable", and the first remote antenna switching system 40a and the second remote antenna switching system 40b correspond to the "remote antenna switching system".

Preferred embodiments of the present invention are as described above, but the present invention is not limited thereto. It will be appreciated that various embodiments are made that do not deviate from the spirit and scope of the invention. Further, in the present embodiment, the actions and effects according to the constitution of the present invention are described, but these actions and effects are examples and do not limit the present invention.

10a 1st antenna switching transmitter 10b 2nd antenna switching transmitter 11 DC voltage generation circuit 12 encoder circuit 13 short circuit detection circuit 14 amplitude control circuit 20a 1st antenna switching receiver 20b 2nd antenna switching receiver 21 Voltage circuit 22 Decoder circuit 23 Switch circuit 24 Detection circuit 30 Coaxial cable 40a First remote antenna switching system 40b Second remote antenna switching system

Claims (3)

In a remote antenna switching system consisting of an antenna switching transmitter and an antenna switching receiver.
A plurality of antennas are connected to the antenna switching receiver, and the antenna is connected to the receiver.
The antenna switching transmitter and the antenna switching receiver are connected by a single coaxial line.
The antenna switching transmitter transmits an RF signal on which a DC voltage selected from three DC voltages is superimposed corresponding to a clock signal and a data signal.
The antenna switching receiver receives the RF signal, detects the DC voltage, separates the clock signal and the data signal, and generates an antenna selection signal using the separated clock signal and the data signal. Then, select one of the specified antennas from the plurality of antennas and connect them.
The correspondence between the clock signal and the data signal and the DC voltage of the three values is
When the clock signal is one of the two values, the DC voltage is low.
When the clock signal is the other of the two values,
If the data signal is one of the two values, the DC voltage has an intermediate height.
If the data signal is the other of the two values, the DC voltage is high and
The antenna switching transmitter includes an encoder circuit and a DC voltage generating circuit.
The encoder circuit generates a ternary signal corresponding to the clock signal and the data signal, and generates a ternary signal.
The DC voltage generation circuit generates a DC voltage corresponding to the ternary signal, and generates a DC voltage.
The output of the antenna switching transmitter is fixed to a specific DC voltage among the three DC voltages after the antenna selection signal transmission is completed, and the specific DC voltage is used as a power source of the antenna switching receiver. Be,
The antenna switching transmitter is a remote antenna switching system further including a short circuit detection circuit. The antenna switching receiver is
Constant voltage circuit and
Decoder circuit and
Including switch circuit,
The constant voltage circuit generates a constant voltage from the DC voltage of the input RF signal.
The decoder circuit separates the clock signal and the data signal from the DC voltage of the RF signal, and further inputs the clock signal and the data signal to the D flip-flop to generate the antenna selection signal.
The remote antenna switching system according to claim 1, wherein the switch circuit conducts a switch with an antenna to be connected based on the antenna selection signal. The remote antenna switching system according to claim 2, wherein the separated clock signal is input to the clock input terminal of the D flip-flop via a delay circuit.

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