JP6921045B2 - Proximity detection device - Google Patents

Description

The present invention relates to a proximity detection device.

Conventionally, a proximity detection device for detecting the proximity of an object has been used.

For example, in Patent Document 1, a code signal in which codes having two values are arranged in a random order at a predetermined period is transmitted by directly performing diffusion modulation with a carrier wave signal of a predetermined frequency, and is reflected by an object. We are proposing a technology to detect that an object is in close proximity by receiving a signal.

In the technique disclosed in Patent Document 1, the signal reflected by the received object is demodulated by the carrier wave signal to generate a demodulated signal. Then, the demodulated signal is divided into two, and one demodulated signal is correlated and demodulated with a code signal delayed by the phase of the signal reflected by an object separated by the distance to be detected to generate the first demodulated signal. NS.

When the demodulated signal includes a signal reflected by an object separated by a distance to be detected, the first demodulated signal is correlated and demodulated with a code signal having the same phase, so that the signal has a strong intensity. On the other hand, when the demodulated signal does not include a signal reflected by an object separated by the distance to be detected, the first demodulated signal is correlated and demodulated with a code signal whose phase does not match, so that the signal has weak intensity. ..

Further, the other distributed demodulated signal is correlated and demodulated with a code signal having a phase uncorrelated with the demodulated signal to generate a second demodulated signal.

Then, the magnitude of the first demodulated signal is compared with the threshold value determined based on the magnitude of the second demodulated signal, and it is detected that the objects are close to each other.

As described above, Patent Document 1 proposes a technique for detecting the proximity of an object by suppressing the influence of unnecessary signals.

Japanese Unexamined Patent Publication No. 6-11299

In the technique disclosed in Patent Document 1 described above, the distance for detecting the proximity of an object is limited to one.

Further, in the technique disclosed in Patent Document 1, in order to expand the range of the distance for detecting that an object is close, a signal reflected by an object separated by the distance to be detected is provided for each of a plurality of distances to be detected. It is necessary to provide a circuit that generates a first demodulated signal that is correlated and demodulated with a code signal delayed by the phase. This causes a problem of increasing the scale of the device.

An object of the present specification is to provide a proximity detection device capable of expanding the range of a distance for detecting the proximity of an object without increasing the scale of the device.

According to the first aspect of the proximity detection device disclosed in the present specification, a code generator that generates a first code signal in which codes having two values are arranged in a random order in a predetermined period, and a first code. A delay circuit that outputs a second code signal including a code in which the code in the signal is sequentially delayed with respect to the phase of the code by a plurality of different delay amounts, and the code in the second code signal is the first code signal. The time of the portion having a different phase with respect to the delay circuit is determined for each delay amount, and the first code signal is directly diffused modulated by the carrier signal of a predetermined frequency, and the modulated signal is output. A device, a transmitter that inputs a modulated signal and outputs a radio signal with a signal strength corresponding to the modulated signal, and a signal strength corresponding to the received radio signal that receives the radio signal reflected by an object. A receiver that outputs the received signal of the above, a first demodulator that inputs the received signal, demodulates it with a carrier signal, and outputs the first demodulated signal, and a second code signal with respect to the first demodulated signal. A band filter that performs correlation demodulation and outputs a second demodulation signal, and a band filter that inputs a second demodulation signal and passes a signal having a frequency in the range between the inverse of a predetermined period and zero. And, the second demodulated signal output from the band filter is integrated for each time of the portion where the code in the second code signal has a different phase from the first code signal. It includes a device and a detector that inputs an integrated value signal and outputs a detection signal when the integrated value signal is larger than a predetermined threshold value.

Further, according to the second form of the proximity detection device disclosed in the present specification, a code generator that generates a first code signal in which codes having two values are arranged in a random order in a predetermined period, and a code generator. A first delay circuit that inputs a 1-code signal and outputs a second code signal whose phase is delayed by a predetermined amount, and a code in the second code signal with a plurality of different delay amounts with respect to the phase of the code. The time of the portion of the second delay circuit that outputs the third code signal including the codes delayed in order and the codes in the third code signal have different phases with respect to the second code signal is determined for each delay amount. The second delay circuit and the second coded signal are directly spread-modulated by a carrier signal of a predetermined frequency to output a modulated signal, and a modulated signal is input to the modulated signal. A transmitter that outputs a radio signal with a corresponding signal strength, a receiver that receives a radio signal reflected by an object and outputs a received signal with a signal strength corresponding to the received radio signal, and an input signal. Then, a first demodulator that demodulates with the carrier signal and outputs the first demodulated signal, and a distributor that inputs the first demodulated signal and distributes it to the first demodulated signal and the second demodulated signal. A second demodulator that performs correlation demodulation with the third code signal for the first first demodulation signal and outputs the second demodulation signal, and a first code signal for the second first demodulation signal. A third demodulator that outputs a third demodulated signal and a second demodulator that inputs a second demodulated signal and passes a signal having a frequency in the range between the inverse of a predetermined period and zero. A 1-band filter, a 2nd band filter that inputs a 3rd demodulated signal and passes a signal having a frequency in the range between the inverse of a predetermined period and zero, and a 2nd band filter output from the 1st band filter. A first integrator that outputs a first integrated value signal including an integrated value obtained by integrating the demodulated signal for each time of a portion in which the code of the third code signal has a different phase with respect to the second code signal, and a second band. A second integrated value signal including an integrated value obtained by integrating the third demodulated signal output from the filter for each time of a portion where the code in the third code signal has a different phase with respect to the second code signal is output. An integrator, a threshold value signal generator that inputs a second integrated value signal and outputs a threshold signal based on the amplitude of the second integrated value signal, and detects when the first integrated value signal is larger than the threshold signal. It is equipped with a detector that outputs a signal.

Further, according to the third aspect of the proximity detection device disclosed in the present specification, a code generator that generates a first code signal in which codes having two values are arranged in a random order in a predetermined period, and a code generator. An advanced circuit that outputs a second code signal including a code in which a code in a 1-code signal is sequentially advanced with a plurality of different advanced quantities with respect to the phase of the code, and the code in the second code signal is the first. The time of the part having different phases with respect to the code signal is directly diffused and modulated by the advanced circuit in which the advanced amount is determined and the first coded signal by the carrier signal of a predetermined frequency, and the modulated signal is output. The demodulator, the transmitter that inputs the modulation signal and outputs the radio signal with the signal strength corresponding to the modulation signal, and the radio signal reflected by the object, and responds to the received radio signal. A receiver that outputs a received signal of signal strength, a first demodulator that inputs a received signal, demodulates it with a carrier signal, and outputs a first demodulated signal, and a second code for the first demodulated signal. Correlation demodulation is performed by the signal, the second demodulator that outputs the second demodulation signal, and the second demodulation signal are input, and a signal having a frequency in the range between the inverse of a predetermined period and zero is passed. Outputs an integrated value signal including an integrated value obtained by integrating the band filter and the second demodulated signal output from the band filter for each time of the portion where the code in the second code signal has a different phase with respect to the first code signal. A detector for inputting an integrated value signal and outputting a detection signal when the integrated value signal is larger than a predetermined threshold value is provided.

Further, according to the fourth aspect of the proximity detection device disclosed in the present specification, a code generator that generates a first code signal in which codes having two values are arranged in a random order in a predetermined period, and a code generator. A first advanced circuit that inputs a 1-code signal and outputs a second code signal whose phase is advanced by a predetermined amount, and a code in the second code signal with a plurality of different advanced quantities with respect to the phase of the code. The time of the portion of the second advanced circuit that outputs the third code signal including the codes that are advanced in order and the codes in the third code signal have different phases with respect to the second code signal is determined for each advanced amount. The second advanced circuit and the second coded signal are directly spread-modulated by a carrier signal of a predetermined frequency and output a modulated signal, and a modulated signal is input to the modulated signal. A transmitter that outputs a radio signal with a corresponding signal strength, a receiver that receives a radio signal reflected by an object and outputs a received signal with a signal strength corresponding to the received radio signal, and an input signal. Then, a first demodulator that demodulates with the carrier signal and outputs the first demodulated signal, and a distributor that inputs the first demodulated signal and distributes it to the first demodulated signal and the second demodulated signal. A second demodulator that performs correlation demodulation with the third code signal for the first first demodulation signal and outputs the second demodulation signal, and a first code signal for the second first demodulation signal. A third demodulator that outputs a third demodulated signal and a second demodulator that inputs a second demodulated signal and passes a signal having a frequency in the range between the inverse of a predetermined period and zero. A 1-band filter, a 2nd band filter that inputs a 3rd demodulated signal and passes a signal having a frequency in the range between the inverse of a predetermined period and zero, and a 2nd band filter output from the 1st band filter. A first integrator that outputs a first integrated value signal including an integrated value obtained by integrating the demodulated signal for each time of a portion in which the code of the third code signal has a different phase with respect to the second code signal, and a second band. A second integrated value signal including an integrated value obtained by integrating the third demodulated signal output from the filter for each time of a portion where the code in the third code signal has a different phase with respect to the second code signal is output. An integrator, a threshold value signal generator that inputs a second integrated value signal and outputs a threshold signal based on the amplitude of the second integrated value signal, and detects when the first integrated value signal is larger than the threshold signal. It is equipped with a detector that outputs a signal.

According to the proximity detection device disclosed in the present specification described above, the range of the distance for detecting the proximity of an object can be expanded without increasing the scale of the device.

It is a figure which shows the structure of the 1st Embodiment of the proximity detection apparatus disclosed in this specification. (A) to (C) are diagrams for explaining the M-sequence code. It is a figure explaining the correlation value of the M sequence code signal. (A) is a diagram for explaining the third demodulated signal C3, (B) is a diagram for explaining signals D3, D5, D6, and B, and (C) is a diagram for explaining a sampling clock. , (D) are diagrams for explaining the detection signal D7. It is a figure explaining the phase of the 3rd code signal. It is a figure explaining the demodulation signal D1. It is a figure explaining the demodulation signal D2. It is a figure explaining the operation of the 2nd Embodiment of the proximity detection apparatus disclosed in this specification, (A) is a figure explaining the 3rd demodulation signal C3, (B) is the figure which explains the signal D3, D5,. It is a figure explaining D6, B, (C) is a figure explaining a sampling clock, (D) is a figure explaining a detection signal D7. It is a figure explaining the 3rd Embodiment of the proximity detection apparatus disclosed in this specification. It is a figure explaining the 4th Embodiment of the proximity detection apparatus disclosed in this specification. It is a figure explaining the 5th Embodiment of the proximity detection apparatus disclosed in this specification.

Hereinafter, a preferred embodiment of the proximity detection device disclosed in the present specification will be described with reference to the drawings. However, the technical scope of the present invention is not limited to those embodiments, but extends to the inventions described in the claims and their equivalents.

FIG. 1 is a diagram showing a configuration of an embodiment of a proximity detection device disclosed in the present specification.

The proximity detection device 10 of the present embodiment (hereinafter, also simply referred to as the device 10) is a device that detects that the object 50 is close to a predetermined distance and outputs a detection signal.

The device 10 includes a signal transmission unit 20 that generates a code signal and transmits a radio signal including the code signal, and a signal detection unit 30 that receives the radio signal and detects the proximity of the object 50.

The signal transmission unit 20 includes a code generator 21, a first delay circuit 22, a modulator 23, an oscillator 24, a transmission unit 25, a second delay circuit 26, and a delay time control unit 43.

The signal detection unit 30 includes a reception unit 31, a first demodulator 32, an amplifier 33, a distributor 34, a second demodulator 35, a third demodulator 36, a first band filter 37, and a second. It includes a band filter 38, a first integrator 39, a second integrator 40, a threshold signal generator 41, a detector 42, and a sampling clock generator 44.

First, the signal transmission unit 20 will be described below.

The code generator 21 generates a first code signal C1 in which codes having two values are arranged in a random order in a predetermined cycle, and outputs the first code signal C1 to the first delay circuit 22. Specifically, the code generator 21 preferably generates a signal having a constant side lobe of the cyclic autocorrelation function as the first code signal. As such a first code signal C1, for example, an M-sequence (Maximum Length Sequence) code signal or a Barker-sequence code signal can be used.

In this embodiment, an M-sequence code signal is used as the first code signal C1. The M-series code signal is, for example, a circuit that uses a shift register having a predetermined number of bits to input the exclusive OR of the output value of the shift register and the feedback tap taken out from the intermediate portion of the shift register to the shift register. Can be generated by driving with the built-in clock.

FIG. 2A is a diagram illustrating one cycle of the M-sequence code signal.

In the time domain display, the M-sequence code signal for one cycle is formed by randomly arranging codes (bits) having two values such as "1" and "-1". When the M-sequence code signal is generated using the N-stage shift register, the number of "1" s contained in the M-sequence code signal for one cycle is 2 ^N-1 , which is "-1". The number is (2 ^N-1 ) -1, and the sequence length CN, which is the total number of bits, is 2 ^N -1.

τ is a subpulse width which is the time length of 1 bit of the M-sequence code signal, and the time length T of one cycle is CN × τ.

The frequency domain display is obtained by Fourier transforming the M-sequence code signal of the time domain display.

Since the M-series code signal in the time domain display has a square signal waveform, the M-series code signal in the frequency domain display has a wide band frequency distribution. The main lobe is in the range of 0 ± 1 / τ, and side lobe vibrations appear on both sides of the main lobe with a period of 1 / τ.

As shown in FIG. 2C, the code generator 21 repeatedly generates an M-sequence code signal in the period T, and continuously outputs the first code signal C1. In this case, the first code signal C1 displayed in the time domain is represented by a convolution of the M-sequence code signal for one cycle shown in FIG. 2 (A) and the delta function sequence shown in FIG. 2 (B).

On the other hand, as shown in FIG. 2B, the delta function sequence is also a delta function sequence in the frequency domain display, and the convolution in the time domain is a product in the frequency domain. Is a frequency spectrum in which, as shown in FIG. It becomes. The frequency spectrum with zero frequency is the reciprocal of the sequence length CN.

FIG. 3 is a diagram for explaining the correlation value of the M-sequence code signal.

The correlation value of the autocorrelation function of the M-sequence code signal is -1 in the region other than the range between the position where the phase shift is 1 bit advanced and the position where the phase is delayed by 1 bit, centering on the position where the phase shift is zero. It becomes. ^{The correlation value is 2 N-} 1 when the phases match (the phase shift is 0). When the phase shift is in the range of 0 ± 1 bit, the correlation value changes linearly in the range of ^{-1 to 2 N-1.} As shown in FIG. 3, in the range of the phase delay of one cycle, in the range of the phase delay of 0 to 1 bit, the correlation value ^{linearly changes from 2N-} 1 to -1, and the phase delay. In the range of 1 bit to 2 ^N- 2, the correlation value is -1 and the side lobe is constant. Further, when the phase delay is in ^{the range of 2 N} -2 to 2 ^N -1 bits, the correlation value changes linearly ^{from -1 to 2 N-1.} A phase lag of 2 ^N- 2 is equivalent to a phase advance of 1 bit.

The addition of the M-series code signal having a predetermined phase and the M-series code signal having another phase as a method of 2 becomes an M-series code signal having yet another phase.

The first delay circuit 22 inputs the first code signal C1 and outputs the second code signal C2 whose phase is delayed by a predetermined amount to the modulator 23 and the second delay circuit 26. The phase amount that the first delay circuit 22 delays the first code signal C1 is, for example, that the radio signal transmitted from the transmitting unit 25 is reflected by the object 50 located at the farthest position and received by the receiving unit 31. It is determined based on the time required for. In the present embodiment, the first delay circuit 22 inputs the first code signal C1 and outputs the second code signal C2 whose phase is delayed by one bit.

The modulator 23 directly performs diffusion modulation on the second code signal C2 by the carrier signal Fc of a predetermined frequency input from the oscillator 24 to generate a modulation signal M1 and output it to the transmission unit 25. The modulator 23 can use phase modulation, amplitude modulation or frequency modulation.

The oscillator 24 oscillates a carrier signal Fc having a predetermined frequency and outputs it to the modulator 23 and the first demodulator 32.

The transmission unit 25 inputs the modulation signal M1 and outputs a radio signal having a signal strength corresponding to the modulation signal M1. As the wireless signal, electromagnetic waves, sound waves, and light can be used. In this embodiment, an electromagnetic wave is used as the wireless signal.

The second delay circuit 26 includes a third code signal C3 including an M-sequence code in which the M-sequence code in the input second code signal C2 is sequentially delayed by a plurality of different delay amounts with respect to the phase of the M-sequence code. Is output. The time of the portion where the M-sequence code in the third code signal C3 has a different phase with respect to the second code signal C2 is determined for each delay amount.

Next, the relationship between the phase of the third code signal C3 and the phase of the second code signal C2 will be described with reference to FIG. 4 (A).

In the device 10, a plurality of different delay amounts of the M-sequence code in the third code signal C3 change in a stepwise manner with respect to the phase of the second code signal C2. The minimum value of the delay amount is the time length of one bit of the code forming the M-sequence code. The delay amount may be the time length of a plurality of bits. Further, the delay amount may be increased by the same phase amount or may be increased by different phase amounts.

The number of distances at which the proximity of the object 50 is detected by the device 10 coincides with the number of different delay amounts. For example, in the example shown in FIG. 4, since the number of the plurality of different delay amounts is 8, the number of distances at which the proximity of the object 50 is detected is also 8. In the device 10, the different delay amounts are increased by the same phase amount.

In the example shown in FIG. 4, first, the second delay circuit 26 generates a third code signal C3 including an M-sequence code delayed by a delay amount of 1 with respect to the phase of the M-sequence code in the second code signal C2. And output.

Next, the second delay circuit 26 generates and outputs a third code signal C3 including an M-sequence code delayed by a delay amount of 2 with respect to the phase of the M-sequence code in the second code signal C2.

Similarly, the second delay circuit 26 sequentially generates a third code signal C3 including an M-sequence code delayed by a delay amount of 3 to 8 with respect to the phase of the M-sequence code in the second code signal C2. And output.

The second delay circuit 26 is controlled by the delay time control unit 43 to determine the temporal length of each delay amount. The delay time control unit 43 describes the temporal length (hereinafter, also referred to as section time) of the portion (interval) in which the M series code in the third code signal C3 has a different phase with respect to the second code signal C2, which will be described later. The second delay circuit 26 is controlled so that the integrated value obtained by integrating the signals during the interval time in the first integrator 39 becomes a magnitude that can be detected by the detector 42 with a difference from the noise.

In the device 10, the delay time control unit 43 controls the second delay circuit 26 so that the section times are all the same.

Next, the signal detection unit 30 will be described below.

The receiving unit 31 receives the radio signal reflected by the object 50, and outputs the received signal M2 having the signal strength corresponding to the received radio signal to the first demodulator 32.

The first demodulator 32 inputs the received signal M2, demodulates it with the carrier signal Fc, and outputs the demodulated signal D to the amplifier 33. Here, the demodulated signal D includes an M-sequence code signal having a phase different from that of the second code signal C2. The phase of this M-sequence code signal is delayed from that of the second code signal C2 by the time required for the radio signal transmitted from the transmission unit 25 to be reflected by the object 50 and received by the reception unit 31. .. Further, the demodulated signal D may include an unnecessary signal caused outside the device 10 or an unnecessary signal caused inside the device 10.

The amplifier 33 amplifies the input demodulation signal D and outputs it to the distributor 34.

The distributor 34 distributes the demodulated signal D to each of the first signal channel CH1 and the second signal channel CH2. The first signal channel CH1 includes a second demodulator 35, a first band filter 37, and a first integrator 39. The second signal channel CH2 includes a third demodulator 36, a second band filter 38, a second integrator 40, and a threshold signal generator 41.

First, the first signal channel CH1 will be described below.

The second demodulator 35 performs correlation demodulation with respect to the demodulated signal D input from the distributor 34 by the third code signal C3, and outputs the demodulated signal D1 to the first band filter 37.

The second demodulator 35 outputs a demodulated signal D1 having a signal strength corresponding to the correlation value between the M-sequence code signal included in the demodulated signal D and the third code signal C3 which is the same M-sequence code signal. The signal strength of the demodulated signal D1 is affected by the phase of the M-series code signal included in the demodulated signal D and the phase of the third code signal C3.

As described with reference to FIG. 3, the phase of the M-sequence code signal included in the demodulated signal D may be less than 1 bit out of phase with respect to the phase of the third-sequence code signal C3, which is the same M-sequence code signal. For example, a demodulation process equivalent to finding an autocorrelation function gives a correlation value greater than -1. Next, the phase of the third code signal C3 will be described below with reference to FIG.

FIG. 5 is a diagram for explaining the phase of the third code signal.

The amount of delay with respect to the phase of the second code signal C2 in the third code signal C3 can be determined based on the distance Rr between the object 50 for which the approach is to be detected and the device 10. When the device 10 and the object 50 are separated by the distance Rr, the time Tr required for the radio signal transmitted from the transmitting unit 25 to be reflected by the object 50 and received by the receiving unit 31 is expressed as 2 × Rr / Vc. Will be done. Here, Vc is the velocity of the electromagnetic wave. Therefore, if the amount of delay with respect to the phase of the second code signal C2 in the third code signal C3 is delayed by the time Tr with respect to the phase of the second code signal C2, the phase of the M series code signal in the third code signal C3. And the phase of the M series code signal included in the demodulated signal D match.

Therefore, if the delay amount of the phase of the M series code in the third code signal C3 with respect to the second code signal C2 is time Tr, the object 50 approaches the device 10 when the object 50 approaches the device 10 at a distance Rr. It is possible to detect what has been done.

In the device 10, the M-series code in the third code signal C3 has a phase that is sequentially delayed by at least two different delay amounts with respect to the phase of the M-series code in the second code signal C2, so that at least 2 The distance between the two objects 50 can be detected.

Specifically, in the apparatus 10, the phase delay amount of the M-sequence code in the third code signal C3 changes to eight stepwise with respect to the phase of the second code signal C2. Therefore, the device 10 can detect eight distances corresponding to eight time Trs.

FIG. 6 is a diagram illustrating the demodulated signal D1.

FIG. 6A shows a time domain display and a frequency domain display of the demodulated signal D on a certain time axis.

FIG. 6B shows the third code signal C3, and the phase of the M-sequence code in the third code signal C3 coincides with the phase of the M-sequence code of the demodulated signal D shown in FIG. 6A. There is.

FIG. 6C shows a demodulated signal D1 generated by the second demodulator 35 correlatively demodulating the demodulated signal D with the third code signal C3. Since the demodulated signal D1 is correlated and demodulated by the third code signal C3 having the same phase, it becomes a signal having a large correlation value. The frequency domain display of the demodulated signal D1 is a line spectrum having a value obtained by multiplying the frequency zero component of the demodulated signal D by CN, which is the sequence length of the M sequence code, as the frequency zero component.

In the example shown in FIG. 4A, the phase of the M-sequence code of the demodulated signal D reflected and demodulated by the object 50 coincides with the phase of the delay amount 5 of the third code signal C3.

The first band filter 37 inputs the demodulated signal D1 and passes a signal having a frequency in the range between the reciprocal (1 / T) of the period of the M-series code signal C1 generated by the code generator 21 and zero. And output to the first integrator 39. Since noise may be generated by correlation demodulation in a frequency region larger than the reciprocal (1 / T) of the period of the first code signal C1, the first band filter 37 removes this noise.

The first integrator 39 has a first amplitude detector 39a and a first interval averaging device 39b.

The first amplitude detector 39a inputs the demodulated signal D1 output from the first band filter 37 to detect the amplitude of the signal, and uses the first amplitude signal D3 including the detected amplitude as the first section averager 39b. Output to. For example, an envelope detector can be used as the first amplitude detector 39a.

The first interval averager 39b is a first amplitude signal D3 for each time length (interval time) of a portion (interval) in which the M series code in the third code signal C3 has a different phase with respect to the second code signal C2. The first average signal D5 including the average value obtained by dividing the integrated value obtained by dividing the integrated value by the interval time is output to the detector 42.

The delay time control unit 43 controls the first section averaging device 39b so that the first section averaging device 39b integrates the first amplitude signal D3 for each section time. In the example shown in FIG. 4A, the portions of the third code signal C3 in which the M-sequence code has a different phase (delay amount) with respect to the second code signal C2 all have the same interval time. Then, the first interval averaging device 39b generates the first average signal D5 including the average value for each interval time of the integrated value obtained by integrating the first amplitude signal D3.

FIG. 4B shows the time variation of the amplitudes of the first amplitude signal D3 and the first average signal D5.

The first amplitude signal D3 generated based on the first demodulated signal D1 that is correlated and demodulated when the phase delay amount of the M series code in the third code signal C3 is 1 to 4 and 6 to 8 is the demodulated signal D. Since the phase and the phase of the third code signal C3 do not match, it has a small amplitude. On the other hand, the first amplitude signal D3 generated based on the first demodulated signal D1 that is correlated and demodulated when the delay amount of the phase of the M series code in the third code signal C3 is 5, is the phase of the demodulated signal D and the third. Since it matches the phase of the code signal C3, it has a large amplitude.

The first average signal D5 generated based on the first amplitude signal D3 generated when the phase delay amount of the third code signal C3 is 1 to 4 and 6 to 8 has a small amplitude. On the other hand, the first average signal D5 generated based on the first amplitude signal D3 generated when the phase delay amount of the third code signal C3 is 5, has a large amplitude.

The first integrator 39 described above may be formed by using a fast Fourier transform and an amplitude detector instead of the first amplitude detector 39a and the first interval averager 39b.

Further, in the first integrator 39 described above, the time for the first interval averaging unit 39b to integrate the first amplitude signal D3 was every interval time, but every interval time and every time across the detached interval, The first amplitude signal D3 may be integrated. This makes it possible to compensate for the effect of data omissions on the average value at the boundaries of adjacent sections. Further, the first integrator 39 may output a signal including an integrated value obtained by integrating the first amplitude signal D3 for each interval time instead of the average value.

The above is the description of the first signal channel CH1.

Next, the second signal channel CH2 will be described below.

The third demodulator 36 performs correlation demodulation with the first code signal C1 on the demodulated signal D input from the distributor 34, and outputs the demodulated signal D2 to the second band filter 38.

The third demodulator 36 outputs a demodulated signal D2 having a signal strength corresponding to the correlation value between the M-sequence code signal included in the demodulated signal D and the first code signal C1 which is the same M-sequence code signal. The signal strength of the demodulated signal D2 is affected by the phase of the M-series code signal included in the demodulated signal D and the phase of the first code signal C1.

As described with reference to FIG. 3, the phase of the M-series code signal included in the demodulated signal D is deviated by 1 bit or more from the phase of the first code signal C1 which is the same M-series code signal. For example, -1 is obtained as a low correlation value.

In the device 10, the phase of the first code signal C1 is one bit ahead of the phase of the second code signal C2, and the phase of the demodulated signal D obtained by demodulating the received signal is the maximum distance that the device 10 can detect. Corresponds to the phase of the received signal reflected from the object located at. Further, since the phase of the M-series coded signal included in the demodulated signal D is usually delayed by one bit or more from the phase of the second coded signal C2, the phase of the M-series coded signal included in the demodulated signal D and the phase of the M-series coded signal are usually the same. It does not match the phase of the 1-code signal C1. Further, in the device 10, the sequence length of the M sequence code is adjusted so that the signal of the received signal having a phase matching with the first code signal C1 is set to be weakened to such an extent that it cannot be detected by the detector 42. There is.

FIG. 7 is a diagram illustrating the demodulated signal D2.

FIG. 7A shows a time domain display and a frequency domain display of the demodulated signal D on a certain time axis.

FIG. 7B shows the first code signal C1 and does not match the phase of the demodulated signal D shown in FIG. 7A.

FIG. 7C shows a demodulated signal D2 generated by the third demodulator 36 correlatively demodulating the demodulated signal D with the first code signal C1. Since the demodulated signal D2 is correlated and demodulated by the first code signal C1 whose phases do not match, it becomes an M series code signal having another phase. The frequency domain display of the demodulated signal D2 is the same as that of the demodulated signal D shown in FIG. 7 (A).

The second band filter 38 inputs the demodulated signal D2 and passes a signal having a frequency in the range between the reciprocal (1 / T) of the period of the M-series code signal C1 generated by the code generator 21 and zero. And output to the second integrator 40. Since noise may be generated by correlation demodulation in a frequency domain whose frequency is larger than the reciprocal (1 / T) of the period of the M-sequence code signal C1, the second band filter 38 removes this noise.

The second integrator 40 has a second amplitude detector 40a and a second interval averaging device 40b.

The second amplitude detector 40a inputs the demodulated signal D2 output from the second band filter 38 to detect the amplitude of the signal, and uses the second amplitude signal D4 including the detected amplitude as the second section averager 40b. Output to. For example, an envelope detector can be used as the second amplitude detector 40a.

The second section averager 40b is a second amplitude signal D4 for each time length (section time) of a portion (section) in which the M series code in the third code signal C3 has a different phase with respect to the second code signal C2. The second average signal D6 including the average value obtained by dividing the integrated value obtained by dividing the integrated value by the interval time is output to the threshold signal generator 41.

The delay time control unit 43 controls the second section averaging device 40b so that the second section averaging device 40b integrates the second amplitude signal D4 for each section time. Then, the second section averager 40b generates the second average signal D6 including the average value for each section time of the integrated value obtained by integrating the second amplitude signal D4.

FIG. 4B shows the time change of the amplitude of the second average signal D6.

The second average signal D6 has a small amplitude at any time when the phase delay amount of the M-sequence code in the third code signal C3 is 1 to 8.

The threshold signal generator 41 inputs the second average signal D6, generates the threshold signal B based on the amplitude of the second average signal D6, and outputs the threshold signal B to the detector 42. In the device 10, the threshold value signal generator 41 obtains the threshold value b by the equation b = S × k + p with respect to the amplitude S of the second average signal D6, and generates the threshold value signal B including the threshold value b. Here, k is a coefficient for obtaining the threshold value, and p is a fixed value that determines the lower limit value of the threshold value. The amplitude S of the second average signal D6 includes electromagnetic and electrical noise inside and outside the device 10.

The detector 42 is controlled by the sampling clock SC input from the sampling clock generator 44, compares the first average signal D5 with the threshold signal B, and the first average signal D5 is larger than the threshold signal B. In this case, the detection signal D7 is output.

Since the first average signal D5 compared with the threshold signal B in the detector 42 also contains electromagnetic and electrical noise inside and outside the device 10, by using the threshold signal B having an adaptive signal strength according to the environment. , The detector 42 can accurately detect the proximity of the object 50 by adapting to the fluctuation of noise.

The sampling clock generator 44 is controlled by the delay time control unit 43, and outputs the sampling clock SC for each time of the portion where the M series code in the third code signal C3 has a different phase with respect to the second code signal C2. do. When the sampling clock SC is input, the detector 42 executes a comparison between the first average signal D5 and the threshold signal B. The sampling clock SC is associated with a stepwise changing phase (delay amount) of the third code signal.

FIG. 4C is a diagram for explaining a sampling clock, and FIG. 4D is a diagram for explaining a detection signal D7.

In the examples shown in FIGS. 4 (C) and 4 (D), the detector 42 is generated based on the first demodulated signal D1 that is correlated and demodulated when the phase delay amount of the third code signal C3 is 5. When the first average signal D5 is input, the detection signal D7 is output.

Since the sampling clock SC when the device 10 outputs the detection signal D7 is associated with the delay amount in which the M series code in the third code signal C3 changes stepwise with respect to the second code signal C2, the detection signal The distance between the device 10 and the object 50 can be determined based on the delay amount of the third code signal when D7 is output.

According to the proximity detection device of the present embodiment described above, the range of the distance for detecting the proximity of an object can be expanded without increasing the scale of the device.

In the proximity detection device of the first embodiment described above, the delay amounts of a plurality of different phases with respect to the second code signal C2 of the M series code in the third code signal have changed so as to increase stepwise. The delay amounts of the plurality of different phases of the code signal with respect to the second code signal C2 of the M series code may be changed so as to decrease stepwise. Further, the delay amounts of the plurality of different phases of the M-sequence code with respect to the second code signal C2 in the third code signal may be changed so as to continuously increase or decrease. Here, when a plurality of different phase delay amounts with respect to the second code signal C2 of the M series code in the third code signal change continuously, the device 10 changes the delay amount by the smallest unit in which the phase can be changed. Means.

Next, another embodiment of the proximity detection device described above will be described below with reference to FIGS. 8 to 11. The detailed description of the first embodiment described above is appropriately applied to the points not particularly described with respect to the other embodiments. Further, the same components are designated by the same reference numerals.

FIG. 8 is a diagram illustrating a second embodiment of the proximity detection device disclosed in the present specification.

In the proximity detection device 10 of the present embodiment, the temporal length of the portion of the third code signal C3 in which the M-sequence code has a different phase with respect to the second code signal C2 is the reception having a phase corresponding to the phase. It is determined based on the signal strength.

In the device 10, the time length of the portion where the M-sequence code in the third code signal C3 has a different phase with respect to the second code signal C2 is the integrated value obtained by integrating the strength of the received signal received by the receiving unit 31. Is predetermined based on the time at which is a predetermined value. Further, this predetermined time is determined so that the integrated value obtained by integrating the demodulated signal for each interval time in the first integrator 39 becomes a magnitude that can be detected by the detector 42 with a difference from the noise. preferable.

The intensity of the received signal transmitted by the transmitting unit 25 and reflected by the object 50 and received by the receiving unit 31 becomes stronger as the distance between the object 50 and the device 10 increases, and becomes weaker as the distance between the object 50 and the device 10 increases. Become. That is, the time for which the integrated value obtained by integrating the intensities of the received signals received by the receiving unit 31 becomes a predetermined value becomes shorter as the distance between the object 50 and the device 10 becomes shorter, and the distance between the object 50 and the device 10 becomes longer. It will be long enough.

Further, the amount of phase delay of the received signal with respect to the transmitted signal decreases as the distance between the object 50 and the device 10 decreases, and increases as the distance between the object 50 and the device 10 increases. The small delay amount of the phase of the M-series code in the third code signal C3 with respect to the second code signal C2 corresponds to the short distance between the object 50 and the device 10, and the M-series code in the third code signal C3. A large amount of delay with respect to the second code signal C2 of the phase corresponds to a long distance between the object 50 and the device 10.

Therefore, the temporal length of the portion of the third code signal C3 in which the M series code has a different phase with respect to the second code signal C2 is shorter as the amount of phase delay with respect to the second code signal C2 is smaller, and the second It is determined that the larger the amount of phase delay with respect to the code signal C2, the longer it becomes.

8 (A) is a diagram for explaining the third demodulated signal C3, FIG. 8 (B) is a diagram for explaining signals D3, D5, D6, and B, and FIG. 8 (C) is a sampling clock. 8 (D) is a diagram for explaining the detection signal D7. The description of FIGS. 4 (A) to 4 (D) is appropriately applied to FIGS. 8 (A) to 8 (D).

The second delay circuit 26 is controlled by the delay time control unit 43, and includes an M series code having different phases so that the delay amount with respect to the phase of the second code signal C2 increases stepwise from 1 to 8. The code signal C3 is generated. The phase delay amount increases stepwise from 1 to 8, and the section time of each delay amount also increases stepwise.

The relationship between the temporal length of the portion of the third code signal C3 in which the M series code has a different phase with respect to the second code signal C2 and the strength of the received signal having a phase corresponding to the phase is determined in advance. It is set in the delay time control unit 43.

For example, the power of the received signal M2 per transmission pulse with respect to a point target is expressed by the following radar equation.
Pt x Gt x Gr x λ ² x σ / ((4π) ³ x R ⁴ )
Here, Pt: transmission power, Gt: transmission antenna gain, Gr: reception antenna gain, λ: wavelength, σ: target radar cross section, R: target distance.

The reception time of the signal for which the power of the received signal obtained based on the above equation is a predetermined integrated value is for each delay amount of the phase in which the M-sequence code in the third code signal C3 is different from that of the second code signal C2. It is determined.

The interval time during which the first integrator 39 and the second integrator 40 of the device 10 integrate the signals is also the time of the portion where the M series code in the third code signal C3 has a different phase with respect to the second code signal C2. Corresponds to the length. Further, the interval at which the sampling clock generator 44 of the apparatus 10 outputs the sampling clock SC is also the temporal length of the portion where the M-sequence code in the third code signal C3 has a different phase with respect to the second code signal C2. Corresponds to.

Other configurations of the device 10 are the same as those of the first embodiment described above.

According to the proximity detection device of the present embodiment described above, the number of observations for detecting an object per unit time can be increased to improve the observation efficiency.

FIG. 9 is a diagram illustrating a third embodiment of the proximity detection device disclosed in the present specification.

The proximity detection device 10 of the present embodiment does not include the first delay circuit, the demultiplexer, and the second signal channel according to the first embodiment described above.

Further, the apparatus 10 inputs the first code signal C1 and sequentially delays the M series code in the first code signal C1 by a plurality of different delay amounts with respect to the phase of the M series code. It differs from the above-described first embodiment in that it includes a delay circuit 45 that outputs a third code signal C3 including a code. The delay circuit 45 executes the same operation as the second delay circuit in the first embodiment described above.

The threshold signal generator 41 independently outputs a predetermined threshold signal B to the detector 42.

In the device 10, the operation of generating the threshold signal B is different from that of the first embodiment described above, but the other configurations are the same as those of the first embodiment.

In the device 10, the delay circuit 45 inputs the first code signal C1 and delays the M series code in the first code signal C1 in order with a plurality of different delay amounts with respect to the phase of the M series code. Although the third code signal C3 was output, the delay circuit 45 may output the third code signal C3 without inputting the first code signal C1. For example, using the delay shift register for the delay circuit 45 that generates the M-series code in synchronization with the M-series generation shift register that generates the M-series code of the code generator 21, the M-series code in the third code signal C3 is A third code signal whose phase is delayed by one bit may be generated by stopping the clock given to the delay shift register by one clock for each time of a portion having a different phase with respect to the first code signal C1. ..

FIG. 10 is a diagram illustrating a fourth embodiment of the proximity detection device disclosed in the present specification.

The proximity detection device 10 of the present embodiment is different from the third embodiment described above in that the advanced circuit 46 is provided instead of the delay circuit and the advanced time control unit 47 is provided instead of the delay time control unit. Other configurations of the device 10 are the same as those in the third embodiment described above.

In the device 10, the advanced circuit 46 inputs the first code signal C1 and sequentially advances the M series code in the first code signal C1 with a plurality of different advanced amounts with respect to the phase of the M series code. The third code signal C3 including the M series code is output. A plurality of different advanced quantities of the M-sequence code in the third code signal C3 with respect to the first code signal C1 may change stepwise or continuously. Here, the continuous change of the advanced quantities having different M-sequence codes in the third code signal with respect to the first code signal C1 means that the advanced quantity is changed by the smallest unit whose phase can be changed in the apparatus 10. means. Further, the time of the portion where the M-sequence code in the third code signal C3 has a different phase with respect to the first code signal C1 is determined for each advanced quantity.

The temporal lengths of the portions of the third code signal C3 in which the M-sequence code has a different phase with respect to the first code signal C1 may all be the same, or a received signal having a phase corresponding to the phase. It may be determined based on the strength of.

In the advanced circuit 46, the advanced time control unit 47 controls and determines the temporal length of the portion where the M-sequence code in the third code signal C3 has a different phase with respect to the first code signal C1.

The advanced time control unit 47 integrates the first amplitude signal D3 and outputs an average value for each time of the portion where the M series code in the third code signal C3 has a different phase with respect to the first code signal C1. The first section averager 39b is controlled.

The sampling clock generator 44 is controlled by the advanced time control unit 47, and outputs the sampling clock SC for each time of a portion of the third code signal C3 having a different phase.

The phase (advanced amount) of the M series code with respect to the first code signal C1 in the third code signal C3 corresponds to the distance to the object 50 to be detected, and the device 10 other than replacing the phase delay amount with the advanced amount. The operation of is the same as that of the third embodiment described above.

In the device 10, the advanced circuit 46 inputs the first code signal C1 and advances the M series code in the first code signal C1 in order with a plurality of different advanced amounts with respect to the phase of the M series code. Although the third code signal C3 was output, the advanced circuit 46 may output the third code signal C3 without inputting the first code signal C1. For example, using the advanced shift register for the advanced circuit 46 that generates the M-series code in synchronization with the M-series generation shift register that generates the M-series code of the code generator 21, the M-series code in the third code signal C3 is The phase is advanced by 1 bit by driving the advanced shift register with a clock having a frequency twice that of the clock driving the M series generation shift register for each time of the portion having a different phase with respect to the first code signal C1. 3rd code signal may be generated.

FIG. 11 is a diagram illustrating a fifth embodiment of the proximity detection device disclosed in the present specification.

The proximity detection device 10 of the present embodiment is provided with the first advanced circuit 48 instead of the first delay circuit and the second advanced circuit 49 instead of the second delay circuit with respect to the first embodiment described above. The difference is that the advanced time control unit 47 is provided instead of the delay time control unit. Other configurations of the device 10 are the same as those in the third embodiment described above.

The first advanced circuit 48 inputs the first code signal C1 and outputs the second code signal C2 whose phase is advanced by a predetermined amount.

The second advanced circuit 49 inputs the second code signal C2 and sequentially advances the M-sequence code in the second code signal C2 by a plurality of different advanced amounts with respect to the phase of the M-sequence code. The third code signal C3 including the sequence code is output. The delay amounts of the plurality of different phases of the M-sequence code with respect to the second code signal C2 in the third code signal C3 may change stepwise or continuously. Here, the time of the portion where the M-sequence code in the third code signal C3 has a different phase with respect to the second code signal C2 is determined for each advanced quantity.

The temporal lengths of the portions of the third code signal C3 in which the M-sequence code has a different phase with respect to the second code signal C2 may all be the same, or a received signal having a phase corresponding to the phase. It may be determined based on the strength of.

In the second advanced circuit 49, the advanced time control unit 47 controls the time length of the portion where the M-sequence code in the third code signal C3 has a different phase with respect to the second code signal C2.

The advanced time control unit 47 is the first demodulated signal D2 filtered for each time (section time) of a portion (section) in which the M-series code in the third code signal C3 has a different phase with respect to the second code signal C2. The first integrator 39 is controlled so as to output the first average signal D5 including the average value obtained by dividing the integrated value obtained by dividing the integrator by the interval time to the detector 42.

Further, the advanced time control unit 47 performs a second demodulation in which the M-series code in the third code signal C3 is filtered for each time (section time) of a portion (section) having a different phase with respect to the second code signal C2. The second integrator 40 is controlled so as to output the second average signal D6 including the average value obtained by dividing the integrated value obtained by integrating the signal D2 by the interval time to the threshold signal generator 41.

The sampling clock generator 44 is controlled by the advanced time control unit 47, and outputs the sampling clock SC for each time of a portion of the third code signal C3 having a different phase.

The phase (advanced amount) of the M series code with respect to the second code signal C2 in the third code signal C3 corresponds to the distance to the object 50 to be detected, and the device 10 other than replacing the phase delay amount with the advanced amount. The operation of is the same as that of the first embodiment described above.

In the present invention, the proximity detection device of the above-described embodiment can be appropriately modified as long as it does not deviate from the gist of the present invention. Further, the constituent requirements of one embodiment can be appropriately applied to other embodiments.

10 Proximity detector 20 Signal transmitter 21 Code generator 22 First delay circuit 23 Modulator 24 Oscillator 25 Transmitter 26 Second delay circuit 30 Signal detector 31 Receiver 32 First demodulator 33 Amplifier 34 Distributor 35 Second Demodulator 36 3rd demodulator 37 1st band filter 38 2nd band filter 39 1st integrator 39a 1st amplitude detector 39b 1st section averager 40 2nd integrator 40a 2nd amplitude detector 40b 2nd section average Integrator 41 Threshold signal generator 42 Detector 43 Delay time control unit 44 Sampling clock generator 45 Delay circuit 46 Advanced circuit 47 Advanced time control unit 48 1st advanced circuit 49 2nd advanced circuit 50 Object

Claims (7)

A code generator that generates a first code signal in which codes having two values are arranged in a random order at a predetermined period.
A delay circuit that outputs a second code signal including a code obtained by sequentially delaying the code in the first code signal with a plurality of different delay amounts with respect to the phase of the code, and the code in the second code signal. However, the time of the portion having a different phase with respect to the first code signal is determined by the delay circuit and the delay circuit.
A modulator that directly performs spread modulation on the first code signal with a carrier signal of a predetermined frequency and outputs a modulated signal.
A transmitter that inputs the modulated signal and outputs a radio signal with a signal strength corresponding to the modulated signal.
A receiving unit that receives the radio signal reflected by an object and outputs a received signal having a signal strength corresponding to the received radio signal.
A first demodulator that inputs the received signal, demodulates it with the carrier signal, and outputs the first demodulated signal.
A second demodulator that performs correlation demodulation on the first demodulated signal with the second code signal and outputs the second demodulated signal,
A band filter that inputs the second demodulated signal and passes a signal having a frequency in the range between the reciprocal of the predetermined period and zero.
An integrated value signal including an integrated value obtained by integrating the second demodulated signal output from the band filter for each time of a portion having a phase different from that of the first code signal in the second code signal is output. Integrator and
A detector that inputs the integrated value signal and outputs a detection signal when the integrated value signal is larger than a predetermined threshold value, and
Proximity detection device equipped with. The proximity detection device according to claim 1, wherein the portions of the second code signal having different phases with respect to the first code signal have the same temporal length. The claim that the temporal length of the portion where the code in the second code signal has a phase different from that of the first code signal is determined based on the strength of the received signal having the phase corresponding to the phase. The proximity detection device according to 1. The proximity detection device according to any one of claims 1 to 3, wherein a plurality of different delay amounts in the second code signal change stepwise. The proximity detection device according to any one of claims 1 to 3, wherein a plurality of different delay amounts in the second code signal change continuously. The proximity detection device according to any one of claims 1 to 5, wherein the number of a plurality of different delay amounts in the second code signal matches the number of distances at which the proximity of an object is detected. A code generator that generates a first code signal in which codes having two values are arranged in a random order at a predetermined period.
A first delay circuit that inputs the first code signal and outputs a second code signal whose phase is delayed by a predetermined amount.
A second delay circuit that outputs a third code signal including a code in which the code in the second code signal is sequentially delayed with respect to the phase of the code by a plurality of different delay amounts, and is the third code signal. The time of the portion where the code in the above has a different phase with respect to the second code signal is determined for each delay amount, and the second delay circuit.
A modulator that directly performs spread modulation of the second code signal with a carrier signal of a predetermined frequency and outputs a modulated signal.
A transmitter that inputs the modulated signal and outputs a radio signal with a signal strength corresponding to the modulated signal.
A receiving unit that receives the radio signal reflected by an object and outputs a received signal having a signal strength corresponding to the received radio signal.
A first demodulator that inputs the received signal, demodulates it with the carrier signal, and outputs the first demodulated signal.
A distributor that inputs the first demodulated signal and distributes it to the first demodulated signal and the second demodulated signal.
A second demodulator that performs correlation demodulation on the first demodulated signal with the third code signal and outputs a second demodulated signal.
A third demodulator that performs correlation demodulation with the first code signal for the second first demodulated signal and outputs a third demodulated signal, and a third demodulator.
A first band filter that inputs the second demodulated signal and passes a signal having a frequency in the range between the reciprocal of the predetermined period and zero.
A second band filter that inputs the third demodulated signal and passes a signal having a frequency in the range between the reciprocal of the predetermined period and zero.
A first integral including an integral value obtained by integrating the second demodulated signal output from the first band filter for each time of a portion where the code in the third code signal has a different phase with respect to the second code signal. The first integrator that outputs the value signal and
A second integral including an integral value obtained by integrating the third demodulated signal output from the second band filter for each time of a portion where the code in the third code signal has a different phase with respect to the second code signal. A second integrator that outputs a value signal and
A threshold value signal generator that inputs the second integrated value signal and outputs a threshold value signal based on the amplitude of the second integrated value signal.
When the first integrated value signal is larger than the threshold signal, a detector that outputs a detection signal and a detector
Proximity detection device equipped with.

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