JP5021973B2 - Distance measuring method and distance measuring device - Google Patents

Description

  The present invention relates to a method and apparatus for measuring a distance between two transceivers by combining the two transceivers.

As a technique for measuring the distance to an object by receiving a reflected wave from the object using a radio wave or an ultrasonic wave and detecting or adjusting a phase difference from the transmitted wave, the following Patent Documents 1 to 3 are provided. Is mentioned.
JP 2004-198306 A JP 2005-308694 A Japanese Patent Laying-Open No. 2005-091214

  The technique of Patent Document 1 forms a PLL (Phase Locked Loop) between a transceiver and a reflector. The reflected wave reflected by the transmitted radio wave or ultrasonic wave hits the object to be measured is divided and compared with the reference signal. The comparison result is input as a control voltage of a voltage controlled oscillator (VCO) through a loop filter (LPF as an integrator is used). An example using modulation / demodulation is also shown.

  The technology of Patent Document 2 is a distance sensor by PLL formation using ultrasonic waves. The phase of the reflected wave and the transmitted wave is compared.

  The technique of Patent Document 3 measures a distance from a logical product of a reflected light from a measurement target of pulsed light having a frequency four times that of a reference signal and a pulsed light having a frequency five times that of the reference signal, and the reference signal. Is.

  Patent Documents 1 to 3 all use a reflected wave from a measurement target. Then, it becomes difficult to perform distance measurement when there is an obstacle between the measurement object and the measurement apparatus that does not reflect radio waves and ultrasonic waves or between the measurement object and the measurement apparatus. In this respect, it is limited to short distance measurements.

  In addition, since the transmitted wave and the received wave use the same frequency wave, the reflected wave from the measurement object cannot be identified when there is reflection from other than the measurement object. Moreover, when the transmitting antenna and the receiving antenna are arranged close to each other (when the measuring device is small), there is a concern that the transmitted radio wave (ultrasonic wave) may be directly received.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a distance measuring device that enables distance measurement even when there are obstacles between them. It is another object of the present invention to provide a distance measuring device that can measure a long distance.

  A first invention is a distance measuring method using a first transceiver and a second transceiver, wherein the first transceiver modulates the first carrier with a transmission data signal whose phase difference can be compared. Is transmitted to the second transceiver, and the second transceiver reproduces the first carrier wave from the signal received from the first transceiver and uses the transmission data signal as a return data signal. By demodulating and frequency-converting the reproduced first carrier wave, a second carrier wave having a different frequency is generated, and the second carrier wave is modulated with a return data signal and transmitted back to the first transceiver. The first transmitter / receiver further regenerates the second carrier wave from the received signal received from the second transmitter / receiver, demodulates the return data signal as the received data signal, and receives the reference signal having a constant frequency. The phase difference from the data signal is zero. As described above, the phase of the transmission data signal is feedback-controlled, the phase difference between the reference signal and the transmission data signal synchronized with the frequency of the reference signal is detected, and the first transceiver and the second transmission / reception are performed based on the phase difference. A distance measuring method characterized by determining a distance to a machine.

  In the second invention, the first transmitter / receiver incorporates the third transmitter / receiver, and the third transmitter / receiver receives the transmission signal, reproduces the first carrier wave, and bypasses the transmission data signal. As a received signal, a second carrier wave having a different frequency is generated by modulating the frequency of the reproduced first carrier wave, and a signal obtained by modulating the second carrier wave with a bypass data signal is received as a received signal. A first state capable of outputting and transmitting to the second transceiver and receiving from the second transceiver; and a second state capable of outputting to the third transceiver and inputting from the third transceiver The phase difference between the reference signal and the transmission data signal synchronized with the frequency of the reference signal obtained in the second state is changed between the state and the zero point of the distance between the first transceiver and the second transceiver. It is characterized by doing.

  According to a third aspect of the present invention, a first state in which the first transceiver can transmit to the second transceiver and receive from the second transceiver, and a second state in which transmission data is bypassed as received data The phase difference between the reference signal and the transmission data signal synchronized with the frequency of the reference signal obtained in the second state is set as the zero point of the distance between the first transceiver and the second transceiver. It is characterized by.

  4th invention is the transmitter / receiver which measures the distance with respect to the reply machine which returns a signal, The data signal generator which generates a transmission data signal, The oscillator which produces | generates a 1st carrier wave, The data signal generator outputs The second carrier wave is regenerated from the modulator that modulates the first carrier wave output from the oscillator by the transmission data signal and transmits the modulated signal to the reply machine, and the received signal obtained by receiving the signal transmitted from the reply machine. A carrier recovery unit, a demodulator that demodulates the reception signal to obtain a reception data signal using the second carrier recovered by the carrier recovery unit, a reference signal oscillator that oscillates a reference signal having a constant frequency, and a reference A first phase difference detector for detecting a phase difference between a reference signal oscillated by a signal oscillator and a received data signal; and a data signal generator for making the phase difference detected by the first phase difference detector zero. A feedback control circuit for changing the phase of the transmission data signal generated by the second phase difference detector, and a second phase difference detector for detecting a phase difference between the reference signal and the transmission data signal synchronized with the frequency of the reference signal. It is characterized by determining the distance between the own transceiver and the return machine based on the phase difference detected by the phase difference detector.

  According to a fifth aspect of the present invention, a detour data demodulator that receives a transmission signal, reproduces the first carrier wave, and demodulates the transmission data signal as a detour data signal, and frequency-converts the reproduced first carrier wave. A second carrier generator for generating a second carrier wave having a different frequency, a bypass data modulator for outputting a signal obtained by modulating the second carrier wave with a bypass data signal as a received signal, A switch that switches between a first state in which transmission and reception from the return unit are possible and a second state in which output to the bypass data demodulator and input from the bypass data modulator are possible; In the two states, the phase difference output from the second phase difference detector is used as a zero point of the distance between the own transmitter / receiver and the return device, and the distance is determined based on the zero point.

  6th invention has a switch which switches between the 1st state in which transmission to a reply machine and reception from a reply machine are possible, and the 2nd state in which transmission data is detoured as received data, The phase difference output from the second phase difference detector is used as the zero point of the distance between its own transmitter / receiver and the return device, and the distance is determined based on the zero point.

  When a data signal obtained by modulating the first carrier wave transmitted from the first transceiver is demodulated by the second transceiver, the second carrier wave is modulated by the second carrier wave, and then reversely transmitted, and then demodulated by the first transceiver. A phase difference (time difference) corresponding to the transmission / reception distance (twice the distance between the first and second transmitters / receivers) occurs between the two round-trip transmissions / receptions. At this time, the phase difference due to the distance at which the signals in the first and second transceivers are transmitted may be ignored, but the third transceiver having the same characteristics as the second transceiver is connected to the first transceiver. You may correct | amend on the basis of the phase difference of the state directly provided in the inside of a machine.

  Furthermore, after the PLL is formed by the first transmitter / receiver and the third transmitter / receiver and the VCO is once stably oscillated, the PLL is switched to the formation of the PLL by the first transmitter / receiver and the second transmitter / receiver. It can be detected as a change in the phase of the data signal that the VCO oscillates stably and the output phase of the VCO changes.

The above distance measuring method can be realized by each of the transceivers configured as in claims 4 to 6 .

  According to the present invention described above, the phase difference of the lower frequency data signal is detected, the higher frequency is used for the carrier wave, and it is only necessary to be able to demodulate the lower frequency data signal, and the distance is measured accurately. Is possible. A device that does not reflect radio waves can also be used as a distance measurement target. Since it is strong against barriers and noise between the first and second transceivers, distance measurement can be performed even when the second transceiver is stowed in a place where it cannot be directly seen. The distance can be measured by diffracting an obstacle as long as the diffraction effect can be expected at a high frequency of 800 MHz or less. Note that there is no interference because transmissions from the first transceiver to the second transceiver and reverse transmission from the second transceiver to the first transceiver use different frequency carriers. That is, unlike the technique of receiving a reflected wave, there is no reverse transmission from anything other than the object to be measured. In addition, the measurement distance range can be easily set and changed by changing the frequency of the data signal.

  The present invention can be used for detecting the position of an article indoors, measuring a distance between a car and a pedestrian, and measuring a distance between vehicles.

  The data signal is preferably a rectangular wave. However, a data signal having an arbitrary waveform can be used as long as the phase difference can be detected. The modulation method is arbitrary, but differential modulation / demodulation is facilitated by phase modulation (PSK). BPSK is particularly preferable. The present invention can be implemented even if amplitude modulation is employed. In the case of distance measurement in the range of about 1 to 10 m, for example, the carrier may be several tens of MHz to 1 GHz and the data signal may be several tens of kHz to 10 MHz. Specific examples are shown below, but the present invention is not limited thereto. Each block diagram shows important components. For example, it is naturally included in the present invention to add a band-pass filter (BPF) or an amplifier such as AGC at a desired location.

  1 and 2 are a block diagram showing the configuration of the first transceiver 1000 constituting the distance measuring apparatus according to the first specific embodiment of the present invention, and the configuration of the second transceiver 2000. FIG. It is a block diagram. FIG. 3 is a block diagram showing a configuration of a third transceiver 3000, which is a part of the first transceiver 1000 shown in FIG. In this embodiment, both the transmission from the first transceiver 1000 to the second transceiver 2000 and the reverse transmission from the second transceiver 2000 to the first transceiver 1000 are both two-phase modulation (BPSK). Is used.

The configuration of the first transceiver 1000 shown in FIG. 1 is as follows. Oscillator 10, phase comparator 11, LPF 12, VCO 13, 1 / N frequency divider 14, oscillator 100, modulator 110, changeover switch SW _T , transmission antenna A _1T , third transceiver 3000, reception antenna A _1R , switching Switch SW _R , carrier recovery circuit (carrier recovery unit) 150, demodulator 160, phase comparator (phase difference detector) 191. The phase comparator 11, LPF 12, VCO 13 and 1 / N divider 14 form a PLL. The modulator 110 includes a multiplier 115 and a differential encoding circuit 116. The carrier regeneration circuit 150 includes a doubler 158, a frequency divider 159, a phase comparator 151, an LPF 152, a VCO 153, and a frequency divider 154. Among these, the phase comparator 151, the LPF 152, the VCO 153, and the frequency divider 154 form a PLL.

Based on a rectangular wave having a frequency f ₀ which is the output of the oscillator 10 having a fixed frequency, such as a crystal oscillator, a PLL composed of a phase comparator 11, LPF 12, VCO 13 and 1 / N frequency divider 14 has a frequency f ₁ . A first carrier wave that is a sine wave is generated. That is, f ₁ = Nf ₀ . On the other hand, a rectangular wave having a frequency f _D which is also an output of the oscillator 100 having a fixed frequency is used as a data signal on the transmission side, and is denoted as D _T. The data signal D _T on the transmission side is differentially encoded by the differential encoding circuit 116 of the modulator 110, and the first carrier wave having the frequency f ₁ is BPSK modulated by the multiplier 115 based on the output.

The output of the multiplier 115 of the modulator 110 is input to the changeover switch SW _T and output to either the transmission antenna A _{1T or} the third transceiver 3000.
On the other hand, the output from the reception antenna A _1R and the third transmitter / receiver 3000 is input to the changeover switch SW _R , and one of the outputs is output to the doubler 158 of the carrier recovery circuit 150 and the multiplier 165 of the demodulator 160. Is done.
The two change-over switches SW _T and SW _R are interlocked. When the change-over switch SW _T outputs the output of the multiplier 115 to the transmission antenna A _1T , the change-over switch SW _R outputs the output from the reception antenna A _1R. Output to the subsequent stage (state shown in FIG. 1).
Conversely, when the changeover switch SW _T outputs the output of the multiplier 115 to the transceiver 3000, the changeover switch SW _R outputs the output from the transceiver 3000 to the subsequent stage.

In any case, the output of the changeover switch SW _R is a modulated signal of the second carrier wave having the frequency f ₂ (≠ f ₁ ). In the carrier regeneration circuit 150, the signal is multiplied by 2 by the frequency multiplier 158 (frequency 2 f ₂ ), divided by 1 / A by the frequency divider 159 (frequency 2 f ₂ / A), the phase comparator 151, LPF 152, VCO 153, A second carrier wave having the frequency f ₂ is generated by the PLL composed of the frequency divider 154 and output to the multiplier 165 of the demodulator 160.

In the demodulator 160, the output of the changeover switch SW _R is BPSK demodulated by the second carrier wave of the frequency f ₂ output from the carrier recovery circuit 150 (multiplier 165), and the differential decoding circuit 167 has a rectangular shape of the frequency f _D. data signal D _R of the reception side is generated a wave.

Thus, the phase difference (time delay) between the reception-side data signal D _R output from the differential decoding circuit 167 of the demodulator 160 and the transmission-side data signal D _T output from the oscillator 100 is determined by the phase comparator (level). The phase difference detector 191 detects the difference.

The configuration of the second transceiver 2000 shown in FIG. 2 is as follows. Reception antenna A _2R , carrier recovery circuit 250, demodulator 260, frequency conversion circuit (frequency conversion unit) 270, modulator 210, and transmission antenna A _2T . The carrier recovery circuit (carrier recovery unit) 250 includes a doubler 258, a frequency divider 259, a phase comparator 251, an LPF 252, a VCO 253, and a frequency divider 254. Among these, the phase comparator 251, the LPF 252, the VCO 253, and the frequency divider 254 form a PLL. The demodulator 260 includes a multiplier 265 and a differential decoding circuit 267. The frequency conversion circuit 270 includes a frequency divider 279, a phase comparator 271, an LPF 272, a VCO 273, and a frequency divider 274. Among these, the phase comparator 271, the LPF 272, the VCO 273, and the frequency divider 274 form a PLL. The modulator 210 includes a multiplier 215 and a differential encoding circuit 216.

The first carrier wave of the modulated frequency f ₁ transmitted from the first transceiver 1000 is received by the receiving antenna A _2R , and the doubler 258 of the carrier recovery circuit 250 and the multiplier of the demodulator 260 are received. Is output to H.265. In the carrier regeneration circuit 250, the frequency is doubled by the doubler 258 (frequency 2f ₁ ), divided by ₁ / A by the frequency divider 259 (frequency 2f ₁ / A), the phase comparator 251, the LPF 252, the VCO 253, A first carrier wave having the frequency f ₁ is generated by the PLL including the frequency divider 254, and is output to the multiplier 265 of the demodulator 260 and the frequency divider 279 of the frequency conversion circuit 270. In this embodiment, since synchronous demodulation is performed, the first carrier wave input to the demodulator is naturally synchronized with the first carrier wave included in the received signal.

In the demodulator 260, the output of the receiving antenna A _2R is BPSK demodulated by the first carrier wave of the frequency f ₁ output from the carrier recovery circuit 250 (multiplier 265), and in the differential decoding circuit 267, the rectangular wave of the frequency f _D is obtained. A data signal that is a wave is generated.

In the frequency conversion circuit 270, the first carrier wave having the frequency f ₁ output from the carrier recovery circuit 250 is divided by the frequency divider 279 into 1 / M ₁ (frequency f ₁ / M ₁ ), and the phase comparator 271. , LPF 272, VCO 273, and 1 / M ₂ frequency divider 274 generate a second carrier wave that is a sine wave of frequency f ₂ (≠ f ₁ ). That is, f ₂ / M ₂ = f ₁ / M ₁ .

Next, the data signal that is a rectangular wave of frequency f _D output from the differential decoding circuit 267 of the demodulator 260 is input to the differential encoding circuit 216 of the modulator 210 and differentially encoded. As a result, the second carrier wave having the frequency f ₂ generated by the frequency conversion circuit 270 is subjected to BPSK modulation by the multiplier 215 and transmitted back from the transmission antenna A _2T to the first transceiver 1000. In the present embodiment, since the first carrier wave is converted into the second carrier wave by frequency conversion using the PLL, it can be said that they are “synchronized”.

The configuration of the third transceiver 3000 shown in FIG. 3 is as follows. Carrier reproduction circuit 350, demodulator 360, frequency conversion circuit (frequency conversion unit) 370, modulator 310, transmission antenna A _2T . The carrier recovery circuit (carrier recovery unit) 350 includes a doubler 358, a frequency divider 359, a phase comparator 351, an LPF 352, a VCO 353, and a frequency divider 354. Among these, the phase comparator 351, the LPF 352, the VCO 353, and the frequency divider 354 form a PLL. The demodulator 360 includes a multiplier 365 and a differential decoding circuit 367. The frequency conversion circuit 370 includes a frequency divider 379, a phase comparator 371, an LPF 372, a VCO 373, and a frequency divider 374. Among these, the phase comparator 371, the LPF 372, the VCO 373, and the frequency divider 374 form a PLL. The modulator 310 includes a multiplier 315 and a differential encoding circuit 316.

Each component of the third transmitter / receiver 3000 in FIG. 3 corresponds to each component of the second transmitter / receiver 2000, and the characteristics are all substantially the same. That is, the components having the same characteristics are used except that the receiving antenna A _2R and the transmitting antenna A _2T are excluded from the configuration of the second transceiver 2000. Therefore, their operations are exactly the same except that the input from the receiving antenna A _2R is replaced with the input from the changeover switch SW _T and the input from the transmitting antenna A _2T is replaced with the input from the changeover switch SW _R.

With the above configuration, when the changeover switches SW _T and SW _R are respectively switched to the transmission antenna A _1T and the reception antenna A _1R in the first transceiver 1000 of FIG. 1 (state shown in FIG. 1), the first of FIG. One transceiver 1000 performs bidirectional communication with the second transceiver 2000 of FIG. Transmission from the first transmitter / receiver 1000 to the second transmitter / receiver 2000 is a first carrier wave of frequency f ₁ , and reverse transmission from the second transmitter / receiver 2000 to the first transmitter / receiver 1000 is frequency f ₂ (≠ Since it is performed on the second carrier of f ₁ ), there is no interference. Moreover, since they are modulated with data signals, the phase comparison of the data signals is easy even in a poor communication environment.

When the first transmitter / receiver 1000 and the second transmitter / receiver 2000 are separated by a distance L, the data signal propagates the distance 2L by bidirectional communication, so the time delay Δt is Δt = 2L / c where c is the speed of light. Become. If Δt is smaller than 1 / f _D which is one cycle of the data signal of frequency f _D , it can be detected as a phase lag (a range of measurable distance L). On the other hand, in terms of the accuracy of Δt, the accuracy is finer than one wavelength of the first and second carrier waves. In general, it is considered that the first and second carrier waves have an accuracy of about a quarter wavelength.

Further, the correction of the distance 0 can be performed by connecting the changeover switches SW _T and SW _R to the input / output of the third transceiver 3000, respectively. That is, the constituent elements of the third transceiver 3000 have the same characteristics as the constituent elements of the second transceiver 2000. Therefore, when the first transceiver 1000 and the second transceiver 2000 perform transmission and reverse transmission, The phase lag in the internal circuit can be detected as the phase lag in the internal circuit when the first transceiver 1000 and the third transceiver 3000 transmit and reversely transmit. Thereby, the phase lag at the time of transmission and reverse transmission with the first transceiver 1000 and the second transceiver 2000 is subtracted from the phase lag in those internal circuits, and when propagating the distance 2L, A phase difference corresponding to the time delay Δt can be obtained.

If the phase delay in the internal circuit is not corrected and ignored, the selector switches SW _T and SW _R and the third transceiver 3000 can be omitted. In this case, the output of the modulator 110 is directly input to the transmission antenna A _1T, and the output of the reception antenna A _1R is directly input to the carrier recovery circuit 150 and the demodulator 160.

[Modification of Example 1]
In the first transmitter / receiver 1000 of FIG. 1, the two fixed-frequency oscillators 10 and 100 are used. However, since the output of the frequency divider is a rectangular wave, one local oscillator 101 is substituted as shown in FIG. It is also possible to do. FIG. FIG. 4A is a block diagram showing a configuration of a first transceiver 1100 according to a modification, FIG. B is a block diagram showing the configuration of the second transceiver 2000 paired therewith. FIG. FIG. 4 shows a modulator 110, a carrier recovery circuit 150, a demodulator 160, changeover switches SW _T and SW _R , antennas A _1T and A _1R , and a third transceiver 3000, which are internal configurations of the A transceiver 1100. The configuration of the second transceiver 2000 of B includes the modulator 110, the carrier recovery circuit 150, the demodulator 160, the changeover switches SW _T and SW _R , the antennas A _1T and A _1R , and the third configuration shown in FIG. The transmitter / receiver 3000 and the second transmitter / receiver 2000 of FIG.

FIG. In the configuration of the first transceiver 1100 of A, the output of the local oscillator 101 that generates a sine wave of frequency f ₁ is input to the modulator 110 and the frequency divider 141. A rectangular wave having a frequency f _D (= f ₁ / N) output from the frequency divider 141 is used as a data signal, and is input to the modulator 110 and the phase comparator 191. FIG. A's first transceiver 1100 and FIG. This modification using the B second transceiver 2000 also operates in the same manner as in the first embodiment.

  In the first embodiment, the frequency of the data signal can be changed by changing the frequency of the oscillator 100, and in the case of a modification thereof, the frequency of the local oscillator 101 or the setting of the frequency divider 141. Thereby, a data signal having a frequency corresponding to the measurement distance range can be generated.

FIG. A and FIG. B is a block diagram showing a configuration of a first transceiver 4000 and a block diagram showing a configuration of a second transceiver 2000 that constitute a distance measuring apparatus according to a specific second embodiment of the present invention. . FIG. Modulator 110, carrier recovery circuit (carrier recovery unit) 150, demodulator 160, change-over switches SW _T and SW _R , antennas A _1T and A _1R , and third transmitter / receiver 3000, which are internal configurations of the A transceiver 4000 And FIG. The second transceiver 2000 of B is configured as shown in FIG. A modulator 110, carrier recovery circuit 150, demodulator 160, change-over switches SW _T and SW _R , antennas A _1T and A _1R , and FIG. A third transceiver 3000, FIG. 2 or FIG. It is the same as the second transceiver 2000 of B.

In the present embodiment, the phase comparator 11, LPF 12, VCO 13, and frequency divider 14 constituting the PLL are configured to close the PLL loop for the first time via the second transceiver 2000 or the third transceiver 3000. Yes. The phase comparator 11 compares the phase of the data signal D _R demodulators 160, and a phase of the output of the oscillator 100 fixed frequency (reference signal). In this embodiment, the phase comparator 11 corresponds to the phase difference detector according to the claimed invention.

FIG. The operation of the first transceiver 4000 of A is greatly different from the configuration of the first embodiment in that the VCO 13 that generates the sine wave of the frequency f ₁ is subjected to PLL control as follows. Assume that the output of the VCO 13 is a sine wave having a frequency f ₁ . As will be described below, during the distance measurement according to the present embodiment, the frequency of the output of the VCO 13 slightly increases and decreases near f ₁ .

The output of the VCO 13 is input to the modulator 110 and the frequency divider 14. The frequency divider 14 outputs a data signal D _T that is a rectangular wave having a frequency f _D = f ₁ / N to the modulator 110. Thus, the modulator 110 modulates the first carrier wave, which is a sine wave of the frequency f ₁ , with the rectangular wave _DT of the frequency f _D = f ₁ / N, and outputs it to the third transceiver 3000 (note that 5A shows the change-over switches SW _T and SW _{R that} are in a state of bidirectional communication with the second transceiver 2000.

Similar to the first embodiment, the third transmitter / receiver 3000 outputs a signal obtained by modulating the second carrier wave, which is a sine wave of frequency f ₂ , with a data signal, which is a rectangular wave of frequency f _D , and reproduces the carrier. the circuit 150 and the demodulator 160, the received data signal D _R is generated.

Received data signal D _R to the output of the demodulator 160, the output of the oscillator 100 (see signal) phase are compared. If there is a phase difference is controlled VCO13 through the LPF 12, and ultimately, the output frequency of the oscillator 100 (see signal) is the same as the received data signal D _R with no phase difference is obtained , The phase of the VCO is fixed. That is, in this state, the frequency f _D of the received data signal D _R and the transmission data signal D _T coincides with the frequency of the output of the oscillator 100 (reference signal), the frequency f ₁ of the VCO13 is fixed at f ₁ = Nf _D Is done. At this time, the phase of the transmission data signal D _T output from the frequency divider 14 is advanced from that of the reception data signal D _R output from the demodulator 160 by the time required to pass through the third transceiver 3000.

Next, the state is switched to a state in which a “data signal PLL” is formed with the second transceiver 2000 by the change-over switches SW _T and SW _R. That is, the first carrier wave of the frequency f ₁ modulated with the data signal is transmitted from the first transmitter / receiver 4000 to the second transmitter / receiver 2000 separated by the distance L, and the distance L is separated from the second transmitter / receiver 2000. Then, the second carrier wave of frequency f ₂ modulated with the data signal is reversely transmitted to the first transceiver 4000. Here, the moment when the change-over switches SW _T and SW _R are switched from the “PLL of the data signal with the third transceiver 3000” to the “PLL of the data signal with the second transceiver 2000”. the received data signal D _R is a time delay to the output of the oscillator 100 by a time component to propagate the distance 2L (reference signal) (phase lag) is to occur.

This is because the time delay (phase delay) is finally eliminated by the “PLL of the data signal with the second transceiver 2000”. At this time, the control voltage of the VCO 13 is once increased to make the frequency higher than f ₁ (the frequencies of the transmission data signal D _T and the reception data signal D _R are also higher than f _D ), and the phase of the reception data signal D _R is changed to an oscillator. allowed to catch up to the phase of the 100 output (reference signal), after overtaking the subsequently received data signal D phase _R of phase of the oscillator 100 output (reference signal), a frequency smaller than f ₁ by lowering the control voltage of the VCO13 (The frequency of the transmission data signal D _T and the reception data signal D _R is also smaller than f _D ), and the feedback control is such that the phase of the reception data signal D _R is delayed to the phase of the output (reference signal) of the oscillator 100. . Eventually, the frequency of the oscillator 100 coincides with the frequency f _{D of the} data signal, and the control voltage of the VCO 13 is also restored. Thus, the phase difference between the transmission data signal D _T output from the frequency divider 14 and the reception data signal D _R output from the demodulator 160 is “PLL of the data signal with the third transceiver 3000”. The state of the “PLL of the data signal with the second transceiver 2000” is larger than the state (the transmission data signal D _T is more advanced than the reception data signal D _R ).

In this case, since the received data signal D _R is the output of the oscillator 100 (see signal) are in phase, the phase difference between the output (reference signal) of the transmission data signal D _T and the oscillator 100, the third transmission and reception It suffices if it can be detected between the case with the device 3000 and the case with the second transceiver 2000. This is executed by the phase comparator 111. Thereby, the distance from the first transceiver 4000 to the second transceiver 2000 can be calculated from the amount of change in the phase difference. In the first transceiver 1100 in FIG. 4, the phase comparator 191 simply compares the transmission data signal D _T and the reception data signal D _R , but in the first transceiver 4000 in FIG. The transmission data signal D _T input to the comparator 111 is a VCO 13 having a frequency f ₁ that is an output “phase advanced” so that the reception data signal D _R is in phase with the reference signal output from the oscillator 100. This is an implementation example in which a PLL is formed between the first transceiver 4000 and the second transceiver 2000.

[Modified example of transmitter 4000]
FIG. C shows a configuration of a first transceiver 4100 that is a modification of the first transceiver 4000. The corresponding second transceiver is shown in FIGS. B or FIG. B second transceiver 2000 may be used. FIG. The C first transmitter / receiver 4100 is configured by short-circuiting the configuration of the third transmitter / receiver 3000.

FIG. The first C transceiver 4100 uses a four-terminal switch SW _T ′ instead of the three-terminal switch SW _T. The three-terminal selector switch SW _R is provided not between the reception antenna A _1R and the carrier recovery circuit 150 and the demodulator 160 but between the demodulator 160 and the phase comparator 11.

First, the four-terminal selector switch SW _T ′ performs the following switching. When the three-terminal selector switch SW _R connects the demodulator 160 and the phase comparator 11, the output of the modulator 110 and the transmission antenna A _1T are connected, and the frequency divider 14 and the selector switch SW _R are connected. Between the output of the modulator 110 and the transmitting antenna A _1T , when the three-terminal selector switch SW _R is switched to the connection side with the frequency divider 14. When connecting the peripheral device 14 and the changeover switch SW _R.

  FIG. The first C transceiver 4100 is shown in FIG. This is a simplified (short circuit) component of the third transmitter / receiver 3000 which is the internal configuration of the first transmitter / receiver 4000 of A, and corresponds to the one in which the third transmitter / receiver 3000 is omitted in the first embodiment. I can say.

[Modification of Example 2]
FIG. 6 shows a modification of the second embodiment. FIG. FIG. 6A is a block diagram showing a configuration of a first transceiver 5000 having the third transceiver 7000 as an internal configuration, FIG. B is a block diagram showing a configuration of the second transceiver 6000. FIG. In this modification, only the first carrier wave with the frequency f ₁ is transmitted from the first transceiver 5000 to the second transceiver 6000 or the third transceiver 7000, and the second transceiver 6000 or the third transceiver 7000 is transmitted. The transceiver 7000 divides the frequency to generate a data signal. That is, FIG. A first transceiver 5000 is shown in FIG. The output of the VCO 13 is directly input to the changeover switch SW _T except for the modulator 110 from the first transceiver 4000 of A. The output of the frequency divider 14 is input only to the phase comparator 111. FIG. A third transmitter / receiver 7000 which is an internal configuration of the first transmitter / receiver 5000 of FIG. The carrier regeneration circuit 350 and the demodulator 360 are removed from the third transceiver 3000, which is the internal configuration of the first transceiver 4000 of A, and the output of the changeover switch SW _T is directly input to the frequency conversion circuit 370 and 1 / N Input to the frequency divider 34. The modulator 310 modulates the second carrier wave having the frequency f ₂ that is the output of the frequency conversion circuit 370 by the output of the 1 / N frequency divider 34. In exactly the same way, FIG. In the second transceiver 6000 of B, the modulator 210 modulates the second carrier wave of the frequency f ₂ that is the output of the frequency conversion circuit 270 with the output of the 1 / N frequency divider 24.

  This modification can be simplified in the illustrated configuration compared to the configuration of the second embodiment.

FIG. C is a block diagram showing the configuration of the first transceiver 5500 using the third transceiver 7500, which is a simplified version of the third transceiver 7000. FIG. At the end of the description of the first embodiment, the configuration in which the phase delay in the internal circuit is ignored has been described. The first C transceiver 5500 is shown in FIG. The first transceiver 5000 of A is reconfigured ignoring the phase lag in the internal circuit. The third transceiver 7500 includes only the 1 / N frequency divider 34, and the demodulator 160 and the carrier recovery circuit 150 are disposed between the changeover switch SW _R and the receiving antenna A _1R . Note that FIG. The first C transceiver 5500 is shown in FIG. B is used in combination with the second transceiver 6000 of FIG. A's first transceiver 5000 and FIG. This is the same as the method of using the combination of the second transceiver 6000 of B.

[Others]
In each of the above-described embodiments, demodulation is performed after the carrier is reproduced. However, as in the Costas method, the carrier reproduction may be performed by feeding back once through the demodulator.

  The present invention can be used for position detection of an article provided with a tag (second transceiver). For example, a storage location such as a passport is not always confirmed, but it is possible to accurately detect a location that needs to be instantly searched when necessary.

  For example, if three first transmitters / receivers are arranged, for example, in a room or area of 10 m square, the position of the article to which the tag (second transmitter / receiver) is attached based on the distance from each first transmitter / receiver. It is also possible to specify.

  If an activation circuit that activates at a high frequency with a different frequency is incorporated for each of the plurality of tags (second transceivers), the first transceiver is activated after only the tag (second transceiver) corresponding to the high frequency is activated. By performing transmission and reception, it is also possible to detect the positions of a plurality of tags (second transceivers) one by one. An example of the activation circuit is a technique disclosed in Japanese Patent Application Laid-Open No. 2004-140805 by the present inventors.

The block diagram which shows the structure of the 1st transmitter / receiver 1000 which comprises the distance measuring apparatus which concerns on the specific 1st Example of this invention. The block diagram which shows the structure of the 2nd transmitter / receiver 2000 which comprises the distance measuring apparatus which concerns on the specific 1st Example of this invention. The block diagram which shows the structure of the 3rd transmitter / receiver 3000 which is a part of 1st transmitter / receiver 1000. FIG. 4). FIG. 3A is a block diagram showing a configuration of a first transceiver 1100 according to a modification. B is a block diagram showing a configuration of a second transceiver 2000 according to a modified example. 5). 4A is a block diagram showing a configuration of a first transceiver 4000 that constitutes a distance measuring device according to a specific second embodiment of the present invention; B is a block diagram showing the configuration of the second transceiver 2000; C is a block diagram showing a configuration of a first transceiver 4100 according to a modification. 6). FIG. 5A is a block diagram showing a configuration of a first transceiver 5000 that constitutes a distance measuring device according to a modification; B is a block diagram showing the configuration of the second transceiver 6000; C is a block diagram showing a configuration of a first transceiver 5500 according to another modification.

1000, 1100, 4000, 4100, 5000, 5500: first transceiver 2000, 6000: second transceiver 3000, 7000, 7500: third transceiver 10, 100, 101: oscillator (frequency fixed)
11, 111, 151, 191, 251, 271, 351, 371: Phase comparator 12, 152, 252, 272, 352, 372: Low-pass filter (LPF, integrator)
13, 153, 253, 273, 353, 373: Voltage controlled oscillator (VCO)
14, 24, 34, 141, 154, 159, 254, 259, 274, 279, 354, 359, 374, 379: Divider 110, 210, 310: Modulator 115, 165, 215, 265, 315, 365 : Multipliers 116, 216, 316: differential encoding circuits 150, 250, 350: carrier recovery circuit (carrier recovery unit)
158, 258, 358: Double multiplication circuit 160, 260, 360: Demodulator 167, 267, 367: Differential decoding circuit 270, 370: Frequency conversion circuit (frequency conversion unit)
A _1T , A _2T : Transmitting antenna A _1R , A _2R : Receiving antenna SW _T , SW _R : Changeover switch (3 terminals)
SW _T ': Changeover switch (4 terminals)

Claims (6)

A distance measuring method using a first transceiver and a second transceiver,
The first transceiver is
A transmission data signal capable of comparing the phase difference, and transmitting a transmission signal obtained by modulating the first carrier wave to the second transceiver;
The second transceiver is
From the signal received from the first transceiver, the first carrier wave is recovered and the transmission data signal is demodulated as a return data signal,
By frequency-converting the reproduced first carrier wave, a second carrier wave having a different frequency is generated,
Modulating the second carrier with the reply data signal and transmitting it back to the first transceiver;
The first transceiver further includes:
From the received signal received from the second transceiver, the second carrier wave is reproduced and the return data signal is demodulated as a received data signal,
Feedback control of the phase of the transmission data signal so that the phase difference between the reference signal having a constant frequency and the reception data signal becomes zero;
Detecting a phase difference between the reference signal and the transmission data signal synchronized with the frequency of the reference signal, and determining a distance between the first transceiver and the second transceiver based on the phase difference. A distance measuring method characterized by The first transceiver includes a third transceiver,
The third transceiver is
Input the transmission signal, regenerate the first carrier wave and demodulate the transmission data signal as a bypass data signal,
By frequency-converting the reproduced first carrier wave, a second carrier wave having a different frequency is generated,
A signal obtained by modulating the second carrier wave with the bypass data signal is output as the received signal;
A first state in which transmission to the second transceiver and reception from the second transceiver are possible, and output to the third transceiver and input from the third transceiver are possible. Switch between two states,
The phase difference between the reference signal obtained in the second state and the transmission data signal synchronized with the frequency of the reference signal is set as a zero point of the distance between the first transceiver and the second transceiver. The distance measuring method according to claim 1. The first transceiver is
Switching between a first state in which transmission to the second transceiver and reception from the second transceiver are possible, and a second state in which the transmission data is bypassed as the received data,
The phase difference between the reference signal obtained in the second state and the transmission data signal synchronized with the frequency of the reference signal is set as a zero point of the distance between the first transceiver and the second transceiver. The distance measuring method according to claim 1. In a transmitter / receiver that measures the distance to a return device that returns a signal,
A data signal generator for generating a transmission data signal;
An oscillator for generating a first carrier wave;
A modulator that modulates the first carrier wave output from the oscillator by the transmission data signal output from the data signal generator and transmits the modulated signal to the return device;
A carrier recovery unit that recovers the second carrier from the received signal obtained by receiving the signal transmitted from the reply device;
A demodulator that demodulates the received signal to obtain a received data signal using the second carrier wave reproduced by the carrier wave reproducing unit;
A reference signal oscillator that oscillates a reference signal having a constant frequency;
A first phase difference detector for detecting a phase difference between the reference signal oscillated by the reference signal oscillator and the received data signal;
A feedback control circuit that changes the phase of the transmission data signal generated by the data signal generator so that the phase difference detected by the first phase difference detector becomes zero;
A second phase difference detector for detecting a phase difference between the reference signal and the transmission data signal synchronized with the frequency of the reference signal, based on the phase difference detected by the second phase difference detector. A transceiver comprising: determining a distance between the transceiver and the reply device. A detour data demodulator that receives the transmission signal, reproduces the first carrier wave, and demodulates the transmission data signal as a detour data signal;
A second carrier generator for generating a second carrier wave having a different frequency by frequency-converting the reproduced first carrier wave;
A bypass data modulator for outputting a signal obtained by modulating the second carrier wave with the bypass data signal as the reception signal;
Switching between a first state in which transmission to the return machine and reception from the return machine is possible and a second state in which output to the bypass data demodulator and input from the bypass data modulator are possible And
Have
In the second state, the phase difference output from the second phase difference detector is set as the zero point of the distance between the own transmitter / receiver and the return device, and the distance is determined based on the zero point. The transceiver according to claim 4. A switch for switching between a first state in which transmission to the reply machine and reception from the reply machine are possible and a second state in which the transmission data is bypassed as the received data;
In the second state, the phase difference output from the second phase difference detector is set as the zero point of the distance between the own transmitter / receiver and the return device, and the distance is determined based on the zero point. The transceiver according to claim 4.

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