JP2006203718A - Transmitter/receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmitter in which leak of a carrier signal is reduced and a receiver capable of exactly and promptly receiving a bipolar pulse by a digital circuit in combination of a pulse switch and homodyne detection to be a mainstream in a radar. <P>SOLUTION: This transmitter/receiver of the present invention is constituted by a digital circuit part 2, a transmitting circuit part 3, a transmitting antenna 4, a receiving circuit part 5, a receiving antenna 6 and a high frequency transmitter 7. The transmitting circuit part 3 has a mixer 12 and a switch 13 inside. The leak of the carrier signal 8 is suppressed by opening/closing the switch 13. The receiving circuit part 5 consists of an IQ demodulator 31, two sets of AD converters 37, 38 and 39, 40 by making two as one set and delay time setting part 41, 42. It is constituted so that an I component 52 and a Q component 53 of the bipolar pulse are sampled by two AD converters, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a transmission circuit and a reception circuit used for distance measurement, communication, and the like, and particularly to a technical field of a transmission circuit and a reception circuit using an impulse signal in a high frequency band.

In recent years, the development of communication and radar using UWB (Ultra Wide Band), which is an ultra-wideband wireless system that applies a high frequency band of several GHz, has been promoted. In particular, a broadband of about 4 to 6 GHz in a quasi-millimeter wave band of 23 to 31 GHz or a millimeter wave band near 79 GHz is used as a band for an on-vehicle radar for measuring a short distance of several tens of meters with high accuracy. I am trying to do.

There is a technique in which an impulse signal used for UWB radar is generated at a relatively low cost using a high-speed switch, a broadband mixer, or the like.

FIG. 7 shows a schematic diagram of a transmission circuit when a short pulse generated by a mixer is used in a radar. For the pulse generation by the mixer 74, an impulse signal 73 (baseband band) from the digital circuit 72 is used. A desired carrier signal 76 is generated by a high-frequency oscillator 75, and an up-converted signal is transmitted to use the impulse signal 73 in a desired frequency band.

As the impulse signal 73, a unipolar signal is usually used. In particular, in a receiving circuit used for communication, in order to apply a template for determining the polarity, a convex pulse (hereinafter referred to as a mountain) and a downward convex pulse are used. It is necessary to sample both (hereinafter referred to as valleys). Therefore, it is necessary to delay the sampling of the other valley or peak with respect to the sampling timing of one peak or valley by delaying the time difference between the peaks and valleys (hereinafter referred to as a delay time). This delay time is a fixed value determined corresponding to a predetermined received signal, and is at most about 1 ns in the unipolar pulse applied to the UWB.

Conventionally, in order to realize the delay time, for example, two microstrip lines are used as a delay circuit, and one microstrip line is made longer by a predetermined distance than the other to realize a time difference. A delay circuit was used.

However, the conventional transmitter / receiver has the following problems.
That is, when the mixer does not have high performance isolation, the carrier signal of the high-frequency transmitter leaks to the transmission antenna side via the mixer and is emitted from the transmission antenna. Therefore, a leak signal is transmitted even while the impulse signal is not output, and the receiver also receives this leak signal. When the leak signal is received by the receiver and the information is accumulated, the impulse signal is reflected by an object and the original signal received by the receiver is masked by the leak signal and detected. There was a problem that it was impossible.

In order to solve the above problem, means for turning off the power source of the high frequency transmitter only during a period when the impulse signal is not output can be considered. In this case, a transient response due to ON / OFF of the high frequency transmitter is conceivable. May adversely affect the impulse signal. Furthermore, the high frequency transmitter may be damaged by repeatedly turning on and off the high frequency transmitter.

On the other hand, with respect to the receiving circuit, an analog delay circuit has been conventionally used to realize the delay time, but it has been difficult to accurately realize the delay time by an analog method. For example, two microstrip lines are used as a delay circuit, and one microstrip line is made longer than the other by a predetermined distance to realize a time difference. In such a delay circuit, a microstrip line is transmitted. At this time, the shape of the pulse is also deteriorated due to attenuation and reflection, and the detection performance of the received signal is deteriorated.

Accordingly, the present invention has been made to solve these problems, and an object of the present invention is to provide a transmitter that reduces carrier signal leakage in a combination of a pulse switch that is mainstream in radar and homodyne detection. To do.
It is another object of the present invention to provide a receiver that accurately realizes the delay time with a digital circuit.

According to a first aspect of the transceiver of the present invention, a predetermined impulse signal generated by a digital circuit is up-converted to a predetermined high frequency band and transmitted from a transmitting antenna, and the impulse signal received by a receiving antenna is transmitted. A transmitter / receiver comprising a receiving circuit for sampling, comprising a high-frequency transmitter for generating a carrier signal of the predetermined high frequency band, wherein the transmitting circuit comprises a mixer for up-converting the impulse signal sequence with the carrier signal; The switch is provided between the high-frequency transmitter and the mixer and is opened and closed by control from the digital circuit. The receiving circuit is configured to downconvert the received signal received by the receiving antenna with the carrier signal. Downconverted with the other mixer LPF (Low Pass Filter) for shaping the waveform of the received signal, a first AD converter for sampling and AD converting the received signal shaped by the LPF at a timing inputted from the digital circuit, and the digital A delay time setting section for delaying the timing input from the circuit by a predetermined time; and a second AD converter for sampling and AD converting the received signal shaped by the LPF at the timing input from the delay time setting means It is the transmitter / receiver characterized by consisting of.

The second aspect is a transceiver characterized in that the switch of the transmission circuit is provided between the mixer and the transmission antenna.

A third aspect uses an IQ demodulator instead of the another mixer and the LPF in the receiving circuit, and converts the I component or the Q component output from the IQ demodulator into the first AD converter and The third AD input to the second AD converter, and the other Q component or I component is sampled and AD converted at the timing inputted from the digital circuit and the timing inputted from the delay time setting means, respectively. The transceiver according to claim 1 or 2, comprising an AD converter and a fourth AD converter.

In a fourth aspect, a radar demodulating unit is added to the receiving circuit, and the timing at which the received signal is sampled is determined using a sampling period when the radar demodulating unit detects a predetermined object. It is the transmitter / receiver characterized by this.

According to a fifth aspect, the timing for sampling the received signal is determined based on a cycle that is sequentially changed and updated within a predetermined time width, and after a predetermined object is detected from the received signal, The transmitter / receiver is determined by fixing the period.

A sixth aspect is a transceiver characterized in that, when the radar demodulator detects that the predetermined object has moved, the fixed period is set again.

A seventh aspect is a transmitter / receiver characterized in that in the receiving circuit, another switch is added between the high-frequency transmitter and the another mixer or the IQ demodulator.

An eighth aspect is a transceiver characterized in that the timing for sampling the received signal is determined based on a timing for generating an impulse signal transmitted from the transmission circuit.

In a ninth aspect, the high-frequency transmitter generates the carrier signal in a quasi-millimeter wave, for example, 26 GHz band, or a millimeter wave, for example, 79 GHz band, and the band of the impulse signal transmitted from the transmission antenna is 4 GHz or more. It is the transmitter / receiver characterized by the above.

As described above, according to the present invention, the provision of the switch significantly reduces the leakage of the carrier signal from the mixer and transmission from the transmission antenna during a period in which the impulse signal is not transmitted. It is possible to provide a transmission circuit that can be used. In addition, by appropriately controlling the switch, not only can the isolation of the switch be increased, but also an excellent effect that an inexpensive switch can be used is obtained.

On the other hand, by using a combination of two AD converters having a predetermined time delay, it is possible to provide a receiving circuit capable of accurately sampling the two polarities of the impulse signal. In addition, by separately sampling the two peaks of the bipolar pulse, an excellent effect that an inexpensive AD converter can be used is obtained.

As described above, the transmitter / receiver composed of the transmission circuit and the reception circuit according to the present invention can provide excellent effects such as low-noise transmission and high-accuracy reception with high cost.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The transmission circuit and the reception circuit according to the present embodiment relate to an impulse signal in a high frequency band composed of bipolar pulses.

FIG. 1 is a schematic diagram showing an overall configuration of a transceiver 1 according to an embodiment of the present invention. The transceiver 1 includes a digital circuit unit 2, a transmission circuit unit 3, a transmission antenna 4, a reception circuit unit 5, a reception antenna 6, and a high frequency transmitter 7.

The digital circuit unit 2 performs control, signal processing, and the like of the transmission circuit unit 3 and the reception circuit unit 5, and can use, for example, an FPGA (Field Programmable Gate Array). Further, the digital circuit unit 2 includes a pulse generation unit 11, which generates a pulse pattern 21 for generating an impulse signal having a predetermined pulse width at a predetermined cycle and provides the pulse pattern 21 to the pulse generation unit 11.

An example of the pulse pattern 21 used in the pulse generator 11 and the impulse signal 22 generated in the pulse generator 11 is shown in FIG. In order to generate the impulse signal 22 from the pulse pattern 21, for example, LVDS can be used as the pulse generator 11.

In FIG. 2, a bipolar pulse is used as the impulse signal 22. The bipolar pulse has a waveform in which an upward convex pulse (crest) and a downward convex pulse (valley) are combined, and the peak is combined after the valley and the peak after the valley. There are two types of fish.

The high-frequency transmitter 7 transmits a carrier signal 8 for transmitting and receiving in a predetermined high frequency band. For example, a 24 GHz band is used as the predetermined high frequency band.

Below, the transmission circuit unit 3 will be described first.
The transmission circuit unit 3 includes a mixer 12 and a switch 13 inside.
The mixer 12 is for up-converting the impulse signal 22 into a predetermined frequency band by multiplying the impulse signal 22 output from the pulse generator 11 and the carrier signal 8 output from the high-frequency transmitter 7. is there. The up-converted impulse signal 22 is transmitted from the transmission antenna 4 to the outside.

The transmission circuit unit 3 of the present invention is characterized in that a switch 13 is provided between the high-frequency transmitter 7 and the mixer 12.

In the conventional transmission circuit as shown in FIG. 7, if the isolation performance of the mixer 74 is not sufficiently high, the carrier signal 76 output from the high frequency transmitter 75 during the period when the impulse signal 73 is not output is There is a risk of leaking from 74 and transmitting from the transmitting antenna 77 to the outside. Mixers with improved isolation performance for signals in the high frequency band have also been developed, but there is a problem that the cost of the transmission circuit increases due to its extremely high price.

For example, when the impulse signal 22 shown in FIG. 2 uses a wide band of 4 GHz or more in the 24 GHz band, the pulse width 23 of the impulse signal 22 is about 500 ps. When such an impulse signal 22 is transmitted at a frequency of 100 MHz or less, the time interval 24 between the impulse signals 22 becomes 10 ns or more. That is, the time when the impulse signal 22 is not transmitted is longer by several tens of times than the time when the impulse signal 22 is transmitted.

When the carrier signal 8 leaks from the mixer 12 and is output from the transmission antenna 4, the leaked carrier signal 8 is output from the transmission antenna 4 for a much longer period than the period during which the impulse signal 22 is transmitted. A part thereof is received by the receiving antenna 6. As a result, there is a problem that the original signal received by reflecting the impulse signal 22 is masked by the signal received by reflecting the leaked carrier signal 8.

Therefore, in the transmission circuit unit 3 of the present invention, the switch 13 is provided between the high-frequency oscillator 7 and the mixer 12, and the carrier signal 8 is output to the mixer 12 by closing the switch 13 only during the period in which the impulse signal 22 is output. In the period in which the impulse signal 22 is not output, the switch 13 is opened and the carrier signal 8 is not output to the mixer 12. Thereby, it is possible to avoid the carrier signal 8 leaking from the mixer 12 and transmitted from the transmission antenna 4 during a period when the impulse signal 22 is not output.

A control signal 25 for opening and closing the switch 13 is generated in accordance with the pulse pattern 21 provided to the pulse generation unit 11 in the digital circuit unit 2 and is output to the switch 13. One example of the control signal 25 for opening / closing the switch 13 and the response of the opening / closing operation of the switch 13 is shown in FIG. 3 in association with the impulse signal 22 generated by the pulse generator 11. In FIG. 3, a graph 26 shows the ratio of the closed state of the switch 13 that opens and closes according to the control signal 25.

It is desirable that the switch 13 is sufficiently closed at least during the period in which the impulse signal 22 is output. Therefore, in consideration of the responsiveness of the switch 13, the control signal 25 is preferably a step signal as shown in FIG. An example of the isolation characteristic of the switch 13 is shown in FIG. 4, and the isolation characteristic 27 of the switch 13 increases as the response time of opening / closing increases, and decreases as the response time decreases. .

In the transmission circuit 3 used for radar or the like, it is important to avoid leakage of the carrier signal 8 as described above. Therefore, the higher the isolation performance of the switch 13, the better.

However, if the response time is made longer than necessary in order to improve the isolation performance, the closing time of the switch 13 including the transition time becomes significantly longer than the pulse width of the impulse signal 22. As a result, the time during which the impulse signal 22 is not output out of the closing time of the switch 13 becomes longer, during which the carrier signal 8 continues to be output to the mixer 12 and leaks from the mixer 12 and is transmitted from the transmitting antenna 4. The influence of will become large.

Therefore, in the transmission circuit unit 3 of the present invention, the carrier signal 8 is prevented from being output to the mixer 12 by appropriately selecting the response time of the switch 13. That is, for example, when the pulse width of the impulse signal 22 is 500 ps, it is preferable to set the response time of the switch 13 to about 1 to 3 ns. Even if the carrier signal 8 leaks from the mixer 12 and is transmitted from the transmission antenna 4 during this period, the leak does not adversely affect the resolution of the radar.

Rather, by setting the response time of the switch 13 to about 1 to 3 ns, not only can the isolation of the switch 13 be improved, but an excellent effect that an inexpensive switch can be used is obtained.

In this embodiment, the switch 13 is provided between the high-frequency transmitter 7 and the mixer 12. However, as another embodiment, the switch 13 can be provided on the downstream side of the mixer 12. As long as the carrier signal 8 can be prevented from leaking from the mixer 12 during the period when the impulse signal 22 is not output, the installation position of the switch 13 is determined as long as the waveform of the impulse signal 22 is not adversely affected. It is not limited to.

Next, a preferred embodiment of the receiving circuit of the present invention will be described with reference to the drawings.
A signal transmitted from the transmission antenna 4 is reflected by an object such as a vehicle or a person and received by the reception antenna 6. In the receiving circuit unit 5 of FIG. 1, the received signal 51 is sent to the IQ demodulator 31, where it is returned again to the baseband and separated into the I component 52 and the Q component 53.

The IQ demodulator 31 branches the received signal 51 received by the receiving antenna 6 and inputs it to the two mixers 32 and 33, while receiving the carrier signal 8 from the high frequency oscillator 7 to the respective mixers 32 and 33. The signal 51 is down-converted again to the baseband band. At this time, the mixer 33 is input with the phase of the carrier signal 8 shifted by π / 2 by the phase adjustment unit 34.

Thereby, the I component and the Q component of the reception signal 51 caused by the phase shift can be separated and extracted by the respective mixers 32 and 33. The extracted I component and Q component are shaped by LPFs (Low Pass Filters) 35 and 36, respectively, and then output from the IQ demodulator 31 as an I component 52 and a Q component 53, respectively.

The I component 52 output from the IQ demodulator 31 is branched and input to the two AD converters 37 and 38, while the Q component 53 is branched and input to the two AD converters 39 and 40.

In the embodiment of the receiving circuit 5 of the present invention shown in FIG. 1, two sets of four AD converters 37, 38, 39, each having two AD converters, are set in order to accurately capture the peaks and valleys of the bipolar pulse. 40 are used. Although it is possible to sample the peaks and valleys of the bipolar pulse with one AD converter, it is necessary to use an AD that can handle a 4 GHz band. However, since a 4 GHz AD converter is expensive, it is a big problem in terms of cost.

On the other hand, by using two AD converters as in the receiving circuit 5 of the present invention and separately sampling the peak and valley of the bipolar pulse, an AD converter that can cope with about 40 MHz is used. And cost can be greatly reduced. Furthermore, signal processing in the digital circuit unit 2 can be performed quickly.

In each combination of two AD converters, one of the AD converters 37 and 39 samples the I component 52 and the Q component 53 at the timing 54 given from the digital circuit section 2. On the other hand, the other AD converters 38 and 40 obtain the timing obtained by delaying the timing 54 given from the digital circuit unit 2 in the delay time setting units 41 and 42 by the delay time, respectively, and delay the delay time by the delay time. The I component 52 and the Q component 53 are sampled at the same timing.

The impulse signal 22 generated and transmitted by the transmission circuit unit 3 of the present invention is created by the clock of the digital circuit unit 2, and the time difference between the peak and valley of the bipolar pulse, which is the waveform of the impulse signal 22, That is, the delay time corresponds to the cycle of the clock. Since the clock cycle is stored as a digital value in the digital circuit unit 2, the delay time can be accurately set in the delay time setting units 41 and 42. This makes it possible to accurately set the delay time, which has been difficult in the prior art, by the delay time setting units 41 and 42 in the receiving circuit unit 5 of the present invention.

The timing 54 for sampling the I component 52 and the Q component 53 is set for each predetermined period T on the basis of a predetermined time in the digital circuit unit 2, and is sent to the AD converters 37 and 39 and the delay time setting units 41 and 42. Is output. The predetermined time may be a timing at which the impulse signal 22 is transmitted from the transmission circuit 3. In addition, the period T can be constant in order to communicate with an object at a predetermined distance, and can be variable when distance measurement is performed as a radar.

Further, when the delay time is τ1, the AD converters 38 and 40 perform sampling at a timing delayed by the delay time τ1 from the timing 54 output from the digital circuit unit 2. FIG. 5 schematically shows the timing at which the AD converters 37, 38, 39, 40 sample the peaks and valleys of the bipolar pulse.

As shown in FIG. 5, for the I component 52, the peak before the bipolar pulse is sampled by the AD converter 37, and the peak after the bipolar pulse is sampled by the AD converter 38. Similarly, for the Q component 53, the peak before the bipolar pulse is sampled by the AD converter 39, and the peak after the bipolar pulse is sampled by the AD converter 40.

In the receiving circuit 5 shown in FIG. 1, in order to sample both peaks and valleys of the bipolar pulse, sampling is performed with two AD converters as one set, but only radar demodulation is used for ranging. In the case of performing it, a single AD converter is also possible. That is, when only radar demodulation is performed, it is not always necessary to capture two peaks of the bipolar pulse, and it is only necessary to know that the impulse signal 22 has been received. Furthermore, when only radar demodulation is performed, the transmission waveform is not necessarily a bipolar pulse, and may be a unipolar pulse.

Further, although the IQ demodulator 31 is used in FIG. 1 to hold the phase information of the received signal 51, it is not always necessary to use the IQ demodulator, and this is used particularly when only ranging is performed for radar. It is also possible not to. When the IQ demodulator is not used, it is necessary to provide a mixer and an LPF for downconverting the received signal 51 instead. In addition, two AD converters are required when performing data demodulation for communication, but one AD converter is sufficient when only radar demodulation is performed.

In FIG. 1, the receiving circuit unit 5 is also provided with a switch 43. This is to prevent the carrier signal 8 from leaking from the mixers 32 and 33 to have any adverse effect on the sampling process except when the received signal 51 is sampled at the timing 54 given from the digital circuit unit 2. .

Another embodiment of the receiving circuit of the present invention will be described below with reference to the drawings.
In FIG. 6, a radar demodulating unit 62 for processing the received signal 51 for distance measurement is added to the receiving circuit unit 5 of FIG. The receiving circuit unit 5 shown in FIG. 1 is a communication data demodulating unit 63 in the present embodiment. Therefore, the receiving circuit unit 61 of this embodiment includes a radar demodulating unit 62 and a data demodulating unit 63.

The radar demodulator 62 includes an IQ demodulator 64 and two AD converters 65 and 66. Further, a switch 67 for cutting off the input of the carrier signal 8 may be provided except when the received signal 51 is sampled. The AD converters 65 and 66 perform sampling at a timing 68 given from the digital circuit unit 2.

In a radar transmitter / receiver for distance measurement, in order to measure the distance to an object, a signal is transmitted from a transmitting antenna, the signal is reflected by the object, and the reflected signal is received by a receiving antenna and sampled. The distance to the object is measured by the time difference until it is done. Specifically, when a signal reflected from the object is detected by repeating transmission / reception while sequentially changing the time (sampling period) from transmission of the transmission signal 69 to sampling (sampling period) by a predetermined time width τ2. The sampling period is determined.

In the present embodiment shown in FIG. 6, the signal transmitted from the transmission circuit unit 3 can be used for both distance measurement and communication. For example, the radar demodulation unit processes the received signal 51 to detect the object. By setting the sampling period when the object is detected to the sampling period of the data demodulator, it is possible to receive a signal from the object.

In the embodiment shown in FIG. 1, the receiving circuit 5 is used for distance measurement and the sampling period T is sequentially changed to detect the target. After the target is detected, the sampling period T is fixed and the target is fixed. It is also possible to perform communication with. Further, when the radar demodulator detects that the object has moved, it is possible to set the fixed period T again and to perform continuous communication with the object.

FIG. 1 is a schematic diagram showing the overall configuration of a transceiver according to an embodiment of the present invention. FIG. 2 shows an embodiment of the pulse pattern 21 used in the pulse generator 11 and the impulse signal 22 generated in the pulse generator 11. FIG. 3 shows an embodiment of an impulse signal, a control signal for opening and closing the switch, and a response of the opening and closing operation of the switch. FIG. 4 shows an example of the isolation characteristics of the switch. FIG. 5 schematically shows the timing at which the peak and valley of the bipolar pulse are sampled by the AD converter. FIG. 6 is a schematic diagram showing an overall configuration of a transmitter / receiver to which a radar demodulator according to another embodiment of the present invention is added. FIG. 7 shows a schematic diagram of a conventional transmission path when short pulses generated by a mixer are used in a radar.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Transceiver 2, 72 ... Digital circuit part 3 ... Transmission circuit part 4, 77 ... Transmission antenna 5, 61 ... Reception circuit part 6 ... Reception antenna 7, 75 ... High frequency transmitters 8, 76 ... Carrier signal 11 ... Pulse generators 12, 32, 33, 74 ... Mixer 13, 67 ... Switch 21 ... Pulse pattern 22, 73 ... Impulse Signal 23 ... Pulse width 24 ... Time interval 25 between impulse signals 25 ... Control signal 26 ... Ratio of switch closed state 27 ... Isolation characteristics 31, 64 ... IQ demodulator 34: Phase adjustment unit 35, 36: LPF
37, 38, 39, 40, 65, 66 ... AD converters 41, 42 ... delay time setting unit 51 ... received signal 52 ... I component 53 ... Q component 54, 68 ... Timing 62 ... Radar demodulation unit 63 ... Data demodulation unit 69 ... Transmission signal

Claims (9)

A transmitter / receiver composed of a transmission circuit that up-converts a predetermined impulse signal generated by a digital circuit to a predetermined high frequency band and transmits it from a transmission antenna, and a reception circuit that samples the impulse signal received by a reception antenna;
A high frequency transmitter for generating a carrier signal of the predetermined high frequency band,
The transmission circuit includes:
A mixer for up-converting the impulse signal train with the carrier signal;
The switch is provided between the high-frequency oscillator and the mixer and is opened and closed by control from the digital circuit, and the receiving circuit is
Another mixer that down-converts the received signal received by the receiving antenna with the carrier signal;
LPF (Low Pass Filter) for shaping the waveform of the received signal down-converted by the another mixer;
A first AD converter that performs sampling and AD conversion at a timing when the reception signal shaped by the LPF is input from the digital circuit;
A delay time setting unit that delays the timing input from the digital circuit by a predetermined time;
A transceiver comprising: a second AD converter that samples and converts the received signal shaped by the LPF at a timing inputted from the delay time setting means. The switch of the transmission circuit is
The transceiver according to claim 1, wherein the transceiver is provided between the mixer and the transmission antenna. In the receiving circuit,
An IQ demodulator is used instead of the another mixer and the LPF, and
While the I component or the Q component output from the IQ demodulator is input to the first AD converter and the second AD converter,
A third AD converter and a fourth AD converter for sampling and AD converting at the timing when the other Q component or the I component is input from the digital circuit and at the timing input from the delay time setting means;
The transceiver according to claim 1 or 2, characterized by comprising: Adding a radar demodulator to the receiver circuit;
4. The timing according to claim 1, wherein the timing at which the received signal is sampled is determined using a sampling period when the radar demodulator detects a predetermined object. 5. The transceiver described. The timing for sampling the received signal is:
Determined based on a cycle that is sequentially changed and updated within a predetermined time width,
After a predetermined object is detected from the received signal, it is determined by fixing the period.
The transceiver according to any one of claims 1 to 3, wherein the transmitter / receiver is provided. 4. The fixed period is set again when the radar demodulator detects that the predetermined object has moved. 5. The method according to claim 1, wherein the fixed period is set again. Transceiver. The receiving circuit is
The transceiver according to any one of claims 1 to 5, wherein another switch is added between the high-frequency oscillator and the another mixer or the IQ demodulator. The timing for sampling the received signal is:
The transceiver according to any one of claims 1 to 6, wherein the transceiver is determined based on a timing of generating an impulse signal transmitted from the transmission circuit. The high-frequency transmitter generates the carrier signal in a quasi-millimeter wave band or millimeter wave band,
The transceiver according to any one of claims 1 to 7, wherein a band of an impulse signal transmitted from the transmitting antenna is 4 GHz or more.

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