JPH10186025A - Fm-cw radar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a device, reduce the cost, and save power consumption by outputting an intermediate frequency signal having a frequency of the sum and difference between the double frequency of the output of an N-multiplication unit and a frequency of the reception signal from an even harmonic wave mixer, and obtaining the distance from a target and relative speed from the output of an A/D converter in a signal process section. SOLUTION: An N-multiplication unit 19 outputs a second local oscillator signal. An even harmonic wave mixer 21 outputs an intermediate frequency signal having the sum and difference between the double frequency of the second local oscillator signal and a frequency of the reception signal. A fundamental wave mixer 10 receives the output of a first amplifier 11a and a first local oscillator signal outputted from an L-multiplication unit 17 and outputs the video signal after frequency conversion. An A/D converter 14 converts the video signal outputted from a second amplifier 11b into a digitized video signal. A signal process section 15 receives the digitized video signal and calculates the distance and relative speed of a target. One intermediate frequency oscillator and one fundamental wave mixer an be omitted, and this device can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a human being mounted on a moving body such as an automobile and using a radio wave to exist around a vehicle.
The present invention relates to an FM-CW radar for detecting a vehicle, an obstacle, and the like.

[0002]

2. Description of the Related Art FIG. 10 shows an example in which an FM-CW radar is mounted in front of a vehicle. In the drawing, 1 is a road, 2a and 2b are first and second vehicles, 3 is a mounted FM-CW radar, 4 is an obstacle such as a telephone pole or a parking vehicle on the road, and 5 is a vehicle passing or crossing a road. A human being.

[0003] Next, the use situation will be described. The FM-CW radar 3 mounted on the vehicle 2b traveling on the road 1 radiates an FM-modulated transmission radio wave forward, and the FM-CW radar 3 transmits the vehicle 2a, the obstacle 4, the human 4 and the like traveling ahead. It receives reflected waves and detects their strength, frequency shift due to Doppler and the propagation time of radio waves, and is used for safety measures such as warning for collision prevention or brake control.
When the FM-CW radar 3 is mounted on the front part of the vehicle as described above, it is necessary to reduce the size of the vehicle in terms of the cooling system and appearance. In addition, since accurate detection measures such as the strength of reflected waves, frequency shifts due to Doppler, and radio wave propagation time occupy a large weight, the signal-to-noise ratio (hereinafter referred to as S /
It is necessary to take measures to improve the N ratio, that is, to reduce the noise figure and improve the FM linearity (linearity).

[0004] Regarding the use situation of such a system, for example, see IEICE Technical Report MW94-48 (1994-0).
9) It is described in "Development of millimeter-wave application system in Japan" and "All of ITS" by Nihon Keizai Shimbun (P62-67).

FIG. 11 is a block diagram showing the configuration of a conventional FM-CW radar, wherein 6a and 6b denote first and second oscillators,
Is a directional coupler, 8 is a transmitting antenna, 9 is a receiving antenna, 10a, 10b, and 10c are first, second, and third fundamental wave mixers, 11a and 11b are first and second amplifiers, and 12 is a distributor. , 13 is a filter, 14 is an A / D converter, and 15 is a signal processing unit.

Next, the operation will be described. In FIG. 11, a first oscillator 6a outputs a high-frequency modulated signal (frequency F _RF ±
Of ΔF, F _RF is a high-frequency component and ± ΔF is a modulation frequency component. ) Is output. The directional coupler 7 outputs a part of the high-frequency modulated signal to the transmission antenna 8 as a transmission signal,
The rest is a local oscillation signal. The transmission antenna 8 outputs a transmission signal toward a target (omitted in the drawing),
Receives a reflected signal from the target and outputs a received signal (of the frequency components F _RF ± ΔF + F _b , F _b is a beat frequency component corresponding to the target distance / speed). The second oscillator 6b outputs a signal having an intermediate frequency (for example, several kHz to GHz), and the distributor 12 outputs the signal having the intermediate frequency.
Is divided into two powers. First fundamental wave mixer 10
“a” receives the received signal and one output of the distributor 12 and converts the frequency. The second fundamental wave mixer 10b receives the output of the first fundamental wave mixer 10a and the local oscillation signal, converts the frequency, and outputs an intermediate frequency signal. The first amplifier 11a amplifies the intermediate frequency signal. Third fundamental wave mixer 10c
Receives the output of the first amplifier 11a and the other output of the distributor 12, converts the frequency, and outputs a video signal. The filter 13 filters the harmonic component of the video signal, and the second amplifier 11b amplifies it. A / D converter 14
Converts the video signal into a digital signal, and the signal processing unit 15
A target distance and a relative speed are derived from the output of the / D converter 14.

Here, the operation will be supplementarily described. FIG.
2 shows an operation principle diagram of the FM-CW radar. FIG. 12 (a)
The curves a transmission signal and the local oscillation signal (of frequency F _RF ± ΔF, F _RF high frequency components, ± [Delta] F is the modulation frequency component), the curve b is the received signal. In the case of the FM-CW radar, a frequency-modulated transmission signal is irradiated on a target, and the reception signal has a delay time twice as long as the distance to the target,
The received signal is frequency-converted by the local oscillation signal.
(B) a video signal having a beat frequency component F _b corresponding to a target distance and speed of the curve c of. Then, the signal processing unit 15 calculates the distance and relative velocity of the target from the frequency F _b. For simplicity of explanation here, if your own speed and the target speed are the same,
That is, the case where the relative speed = 0 is shown.

Here, the FM linearity of the oscillator 6 and S
The relationship between the / N ratio will be described. FIG. 13 shows FM-CW
4 shows the effect of FM linearity on radar. In the figure,
A curve a in FIG. 7A is an ideal output characteristic of the oscillator 6, a curve b is an actual output characteristic of the oscillator 6, a curve c is a spectrum of an ideal video signal, and a curve d is an actual video signal. It is a spectrum. When a sawtooth voltage (or a triangular wave) is input to the oscillator 6, ideally, the output frequency is desired to be changed linearly as shown by a curve a.
It becomes a non-linear change like Therefore, in the case of the ideal curve a, the video signal is obtained as a steep spectrum at the beat frequency corresponding to the distance to the forward target as shown by the curve c in (b), but actually, as shown by the curve d. The spectrum has a wide band. Since the FM-CW radar obtains the distance and the relative speed to the forward target from the spectrum of the video signal, when the spectrum has a wide band as shown by the curve d, the S / N ratio is reduced, and the target is obtained with high accuracy. It becomes difficult to measure the distance and the relative speed of the vehicle.

When an FM-CW radar is mounted on an automobile or the like, it is necessary to reduce the size and power consumption in view of various devices and appearance of the vehicle. However, the conventional configuration shown in FIG. It becomes complicated, large size, high cost,
This leads to higher power consumption. Therefore, when mounted and used in a car or the like, the mountability to a car, mass productivity (low cost) and the like are deteriorated, and it is necessary to add a power supply and the like.

[0010]

SUMMARY OF THE INVENTION The above conventional F
When the M-CW radar is mounted on the front part of the vehicle, there has been a problem that it is necessary to reduce the size and power consumption of the vehicle in terms of a cooling system, an electric system, and appearance. In addition, there has been a problem that noise figure reduction and improvement of FM linearity are required for accurate safety measures.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an intermediate frequency signal oscillation system is omitted by obtaining a signal having an intermediate frequency by dividing a local oscillation signal of a transmission signal. An object is to reduce the size and power consumption of an FM-CW radar. Another object of the present invention is to reduce a noise figure of a receiving system by using an even harmonic mixer using an anti-parallel diode pair.
Further, by using an oscillator using a super step junction varactor diode, FM linearity is improved.

[0012]

SUMMARY OF THE INVENTION According to the first aspect of the present invention, an FM-
The CW radar includes an oscillator, a directional coupler, a transmitting and receiving antenna, a K divider and an M divider for dividing the frequency of the local oscillation signal by K and M (K and M are two or more). integer)
An L multiplier and an N multiplier (L and N are integers of 1 or more) for multiplying the frequency-divided local signal by L and N, and a frequency converter that receives and outputs the output of the N multiplier and the received signal. A first fundamental wave mixer, a second fundamental wave mixer for frequency-converting a frequency of a signal output from the first fundamental wave mixer and an output frequency of the L multiplier, an A / D converter, and an A / D converter And a signal processing unit that obtains the distance to the target and the relative speed from the output of.

An FM-CW radar according to a second aspect of the present invention includes an oscillator, a directional coupler, a transmitting and receiving antenna, a frequency divider for dividing the frequency of a local oscillation signal by two, and a frequency divider for two. A power divider for distributing the output of the mixer, a first fundamental wave mixer for receiving one of the outputs of the divider and the received signal and converting the frequency, a first fundamental wave mixer for outputting the frequency of the output signal and the divider for output A second fundamental wave mixer for performing frequency conversion from the frequency of the other output to be processed, an A / D converter, and a signal processing unit for obtaining a distance to a target and a relative speed from an output of the A / D converter.

An FM-CW radar according to a third aspect of the present invention provides an oscillator, a directional coupler, a transmitting and receiving antenna, a K divider that divides the frequency of a local oscillation signal by K and M, and An M frequency divider (K and M are integers of 3 or more), an L frequency multiplier and an N frequency multiplier (L and N are integers of 1 or more) for multiplying the divided local signal by L and N; An even harmonic mixer that incorporates an anti-parallel diode pair in which two diodes of polarities are connected in parallel, and outputs an intermediate frequency signal having a sum and difference frequency between the double frequency of the output of the N multiplier and the frequency of the received signal. A fundamental wave mixer for performing frequency conversion from the frequency of the intermediate frequency signal and the frequency of the output of the L multiplier;
A D converter and a signal processing unit for obtaining a distance and a relative speed to a target from an output of the A / D converter are provided.

Further, an FM-CW radar according to a fourth aspect of the present invention provides an oscillator, a directional coupler, a transmitting and receiving antenna, a three-frequency divider for dividing the frequency of a local signal by three, and a three-frequency divider. And a built-in anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel. The sum and difference of the double frequency of one output of the divider and the frequency of the received signal are included. An even harmonic mixer for outputting an intermediate frequency signal having a frequency, a fundamental wave mixer for performing frequency conversion from the frequency of the intermediate frequency signal and the frequency of the other output of the distributor, an A / D converter, and an A / D converter And a signal processing unit that obtains the distance to the target and the relative speed from the output of.

The FM-CW radar according to a fifth aspect of the present invention provides an oscillator, a directional coupler, a transmitting and receiving antenna, a K divider for dividing the frequency of a local oscillation signal into K and M, and An M frequency divider (K and M are integers of 3 or more), an L frequency multiplier and an N frequency multiplier (L and N are integers of 1 or more) for multiplying the divided local signal by L and N; A first even pair that includes an anti-parallel diode pair in which two diodes of polarities are connected in parallel, and outputs an intermediate frequency signal having a sum and difference frequency between the double frequency of the output of the N multiplier and the frequency of the received signal; A harmonic mixer, and a second even harmonic mixer having a built-in anti-parallel diode pair and outputting a video signal having a frequency of the sum and difference between the double frequency of the output of the L multiplier and the frequency of the intermediate frequency signal. , A / D converter and A / D converter
A signal processing unit for obtaining the distance to the target and the relative speed from the output of the D converter.

Further, an FM-CW radar according to a sixth aspect of the present invention provides an oscillator, a directional coupler, a transmitting and receiving antenna, a frequency divider for dividing the frequency of a local oscillation signal by four, and a frequency divider for four. And a built-in anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel. The sum of the double frequency of one output of the distributor and the frequency of the output signal of the receiving antenna And a first even harmonic mixer that outputs an intermediate frequency signal having a frequency of the difference and a built-in anti-parallel diode pair, and the sum and difference between the double frequency of the other output of the distributor and the frequency of the intermediate frequency signal , A second even harmonic mixer that outputs a video signal having the following frequency, an A / D converter, and a signal processing unit that obtains the distance to the target and the relative speed from the output of the A / D converter.

An FM-CW radar according to a seventh aspect of the present invention is an oscillator having a super step junction diode, an X-multiplier for multiplying the output frequency of the oscillator by X, a directional coupler, a transmitting and receiving antenna. And a K frequency divider and an M frequency divider for dividing the frequency of the local oscillation signal by K and M (K and M are 2
L and N multipliers (L and N are integers of 1 or more) for multiplying the frequency-divided local signal by L and N (L and N are integers of 1 or more), and receiving the output of the N multiplier and the received signal. A first fundamental wave mixer for frequency conversion, a second fundamental wave mixer for frequency-converting an output frequency of the first fundamental wave mixer and an output frequency of the L multiplier and outputting a video signal, and A / D conversion And a signal processing unit for obtaining the distance and relative speed to the target from the output of the A / D converter.

An FM-CW radar according to an eighth aspect of the present invention provides an oscillator, a directional coupler, a transmission / reception switch, a transmission / reception antenna, and a K divider that divides the frequency of a local signal by K and M. A frequency divider and an M divider (K and M are integers of 2 or more);
An L multiplier and an N multiplier (L and N are integers of 1 or more) for L-multiplying and N-multiplying the frequency-divided local oscillation signal; A fundamental wave mixer, a second fundamental wave mixer that frequency-converts an output frequency of the first fundamental wave mixer and an output frequency of the L multiplier and outputs a video signal, an A / D converter, and an A / D converter A signal processing unit for obtaining a distance to the target and a relative speed from the output of the converter.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a diagram showing an embodiment 1 of the present invention.
FIG. 3 is a block diagram of the M-CW radar, in which 6 is an oscillator, 7a and 7b are first and second directional couplers,
8 is a transmitting antenna, 9 is a receiving antenna, 10a and 10
b is first and second fundamental wave mixers, 11a and 11b are first and second amplifiers, 13 is a filter, and 14 is an A / D
Converter, 15 is a signal processing unit, 16 is a K frequency divider, 17 is L
A multiplier, 18 is an M frequency divider, and 19 is an N multiplier.

Next, the operation will be described. In FIG. 1, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) emitted from a transmission antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is A high frequency component, ± ΔF is a modulation frequency component.) The first directional coupler 7a and the second directional coupler 7b output a part of the output of the oscillator 6 as a transmission signal and output the rest as first and second local reference signals. The K frequency divider 16 divides the frequency of the first local oscillation reference signal by K (where K is 2).
The L multiplier 17 multiplies the output frequency of the K frequency divider 16 by L (L is an integer of 1 or more), and outputs a first local oscillation signal. The M divider 18 divides the frequency of the second local reference signal by M (M is an integer of 2 or more), and the N multiplier 19 multiplies the output frequency of the M divider 18 by N ( N is an integer of 1 or more), and outputs a second local oscillation signal. The transmission antenna 8 irradiates a transmission signal to a target. Receiving antenna 9
Receives the reflected signal from the target and receives the signal (FIG. 12).
It corresponds to the curve b in (a). ) Is output. First
Receives the received signal and the second local oscillation signal, converts the frequency, and outputs an intermediate frequency signal. The first amplifier 11a power-amplifies the intermediate frequency signal. The second fundamental wave mixer 10b includes a first amplifier 11a
, And the frequency of the first local oscillation signal, and outputs a video signal (corresponding to the curve c in FIG. 12B). The filter 13 filters the harmonic component of the video signal. The second amplifier 11b amplifies the video signal output from the filter 13. The A / D converter 14 digitally converts the video signal output from the second amplifier 11b. The signal processing unit 15 receives the digitized video signal and derives a target distance and a relative speed. As described above, in the present embodiment, as compared with the conventional configuration, one intermediate frequency oscillator and one fundamental wave mixer can be omitted, so that the device can be downsized.
This makes it possible to reduce the cost and power consumption, and to improve the mountability and mass productivity in automobiles and the like.

However, the values of N, M, L and K cited here require the relationship of Equation 1.

[0023]

(Equation 1)

Embodiment 2 FIG. FIG. 2 is a block diagram of an FM-CW radar showing a second embodiment of the present invention. In the figure, 6 is an oscillator, 7 is a directional coupler, 8 is a transmitting antenna, 9 is a receiving antenna, 10a and 10b. Are first and second fundamental wave mixers, 11a and 11b are first and second amplifiers, 12 is a distributor, 13 is a filter, and 14 is A
A / D converter, 15 is a signal processing unit, and 20 is a divide-by-2 frequency divider.

Next, the operation will be described. 2, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) emitted from a transmitting antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is A high frequency component, ± ΔF is a modulation frequency component.) The directional coupler 7 outputs a part of the output of the oscillator 6 as a transmission signal, and outputs the rest as a local oscillation reference signal. The ２ frequency divider 20 divides the frequency of the local oscillation reference signal by two. The divider 12 distributes the power of the output of the frequency divider 2 to power. The transmission antenna 8 irradiates a transmission signal to a target. The receiving antenna 9 is
Upon receiving the reflected signal from the target, the received signal (FIG. 12A)
Corresponds to curve b. ) Is output. The first fundamental wave mixer 10a receives the received signal and one output of the distributor 12, converts the frequency, and outputs an intermediate frequency signal.
The first amplifier 11a power-amplifies the intermediate frequency signal. The second fundamental wave mixer 10b includes a first amplifier 11a
, And the other output of the distributor 12, frequency conversion is performed, and a video signal (corresponding to the curve c in FIG. 12B) is output. The filter 13 filters the harmonic component of the video signal. Second amplifier 11b
Amplifies the video signal output from the filter 13. The A / D converter 14 digitally converts the video signal output from the second amplifier 11b. Signal processing unit 1
5 receives the digitized video signal and derives the target distance and relative speed. As described above, in the present embodiment, as compared with the conventional configuration, the intermediate frequency oscillator 1
And one fundamental wave mixer can be omitted, and furthermore, a frequency divider and a multiplier can be omitted as compared with the first embodiment, so that the device can be reduced in size, cost and power consumption can be reduced.
It is possible to improve the mountability on a car and the like and the mass productivity.

Embodiment 3 FIG. FIG. 3 is a block diagram of an FM-CW radar showing a third embodiment of the present invention, in which 6 is an oscillator, 7a and 7b are first and second directional couplers, 8 is a transmitting antenna, 9 is a receiving antenna,
10 is a fundamental wave mixer, 11a and 11b are first and second mixers.
Amplifier, 13 a filter, 14 an A / D converter, 15
Is a signal processing unit, 16 is a K frequency divider, 17 is an L multiplier, 18
Is an M frequency divider, 19 is an N multiplier, 21 is a built-in anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel, and the sum and difference of the double frequency of the local oscillation signal and the frequency of the reception signal are incorporated. This is an even harmonic mixer that outputs a signal having a frequency.

Next, the operation will be described. In FIG. 3, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) emitted from a transmitting antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is A high frequency component, ± ΔF is a modulation frequency component.) The first directional coupler 7a and the second directional coupler 7b output a part of the output of the oscillator 6 as a transmission signal and output the rest as first and second local reference signals. The K divider 16 divides the frequency of the first local oscillation reference signal by K (K is 3).
The L multiplier 17 multiplies the output frequency of the K frequency divider 16 by L (L is an integer of 1 or more), and outputs a first local oscillation signal. The M divider 18 divides the frequency of the second local oscillation reference signal by M (M is an integer of 3 or more), and the N multiplier 19 multiplies the output frequency of the M divider 18 by N times ( N is an integer of 1 or more), and outputs a second local oscillation signal. The transmission antenna 8 irradiates a transmission signal to a target. Receiving antenna 9
Receives the reflected signal from the target and receives the signal (FIG. 12).
It corresponds to the curve b in (a). ) Is output. The even harmonic mixer 21 outputs an intermediate frequency signal having a sum and difference frequency between the double frequency of the second local oscillation signal and the frequency of the reception signal. The first amplifier 11a power-amplifies the intermediate frequency signal. The fundamental wave mixer 10 includes the first amplifier 1
Receiving the output of 1a and the first local oscillation signal, frequency conversion is performed, and a video signal (corresponding to a curve c in FIG. 12B).
Is output. The filter 13 filters the harmonic component of the video signal. The second amplifier 11b amplifies the video signal output from the filter 13. A /
The D converter 14 converts the video signal output from the second amplifier 11b into a digital signal. The signal processing unit 15 receives the digitized video signal and derives a target distance and a relative speed. Thus, in the present embodiment,
Compared to the conventional configuration, the configuration can be omitted by omitting one oscillator of the intermediate frequency and one fundamental wave mixer, so that the device can be reduced in size, price and power consumption, and can be applied to automobiles and the like. The mountability and mass productivity can be improved.

Next, the noise characteristics of the fundamental wave mixer and the even harmonic mixer will be described. FIG. 4 shows a noise voltage included in the video signals output from the fundamental wave mixer 10 and the even harmonic mixer 21. In the figure, a curve a represents the fundamental wave mixer 10 and a curve b represents the noise voltage included in the video signal output from the even harmonic mixer 21. Thus, it can be seen that the noise voltage of the even harmonic mixer 21 is much lower than the noise voltage of the fundamental mixer 10. Therefore,
When the even harmonic mixer 21 is used, the noise figure of the receiving system of the FM-CW radar is improved, the distance performance of the FM-CW radar can be improved, and accurate safety measures can be taken.

However, the values of N, M, L and K cited here require the relationship of equation (2).

[0030]

(Equation 2)

Embodiment 4 FIG. FIG. 5 is a block diagram of an FM-CW radar showing a fifth embodiment of the present invention. In the figure, 6 is an oscillator, 7 is a directional coupler, 8 is a transmitting antenna, 9 is a receiving antenna, and 10 is a 1st and 2nd fundamental wave mixers, 11a and 11b are 1st and 2nd amplifiers,
12 is a distributor, 13 is a filter, 14 is an A / D converter,
Reference numeral 15 denotes a signal processing unit, reference numeral 21 denotes a built-in anti-parallel diode pair in which two diodes having opposite polarities are connected in parallel,
The even harmonic mixer 22 outputs a signal having a frequency of the sum and difference between the frequency of the local oscillation signal and the frequency of the reception signal, and 22 is a frequency divider.

Next, the operation will be described. 5, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) irradiated from a transmitting antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is A high frequency component, ± ΔF is a modulation frequency component.) The directional coupler 7 outputs a part of the output of the oscillator 6 as a transmission signal, and outputs the rest as a local oscillation reference signal. The three-frequency divider 22 divides the frequency of the local oscillation reference signal by three. The divider 12 distributes the power of the output of the 3 divider 22. The transmission antenna 8 irradiates a transmission signal to a target. The receiving antenna 9 is
Upon receiving the reflected signal from the target, the received signal (FIG. 12A)
Corresponds to curve b. ) Is output. The even harmonic mixer 21 outputs an intermediate frequency signal having a sum and difference frequency between the double frequency of one output of the divider 12 and the frequency of the received signal. The first amplifier 11a power-amplifies the intermediate frequency signal. The fundamental wave mixer 10 receives the output of the first amplifier 11a and the other output of the distributor 12, converts the frequency, and outputs a video signal (corresponding to a curve c in FIG. 12B). The filter 13 filters the harmonic component of the video signal. Second amplifier 1
1b amplifies the video signal output from the filter 13. The A / D converter 14 digitally converts the video signal output from the second amplifier 11b. The signal processing unit 15 receives the digitized video signal and derives a target distance and a relative speed. As described above, in the present embodiment, one intermediate frequency oscillator and one fundamental wave mixer can be omitted as compared with the conventional configuration, and the frequency divider and the Since the multiplier and the like can be omitted, the size, cost, and power consumption of the device can be reduced, and the mountability and mass productivity of a vehicle or the like can be improved. Further, by using the even harmonic mixer 21, the noise figure of the receiving system is improved, the distance performance of the FM-CW radar can be improved, and accurate safety measures can be taken.

Embodiment 5 FIG. FIG. 6 is a block diagram of an FM-CW radar showing a fifth embodiment of the present invention, in which 6 is an oscillator, 7a and 7b are first and second directional couplers, 8 is a transmitting antenna, 9 is a receiving antenna,
11a and 11b are first and second amplifiers, 13 is a filter, 14 is an A / D converter, 15 is a signal processing unit, 16 is a K divider, 17 is an L multiplier, 18 is an M divider, 19 is N
Each of the multipliers 21a and 21b incorporates an anti-parallel diode pair in which two diodes of opposite polarities are connected in parallel, and outputs a signal having a sum frequency and a difference frequency between the twice frequency of the local oscillation signal and the frequency of the reception signal. The first and second even harmonic mixers.

Next, the operation will be described. 6, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) emitted from a transmitting antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is A high frequency component, ± ΔF is a modulation frequency component.) The first directional coupler 7a and the second directional coupler 7b output a part of the output of the oscillator 6 as a transmission signal and output the rest as first and second local reference signals. The K divider 16 divides the frequency of the first local oscillation reference signal by K (K is 3).
The L multiplier 17 multiplies the output frequency of the K frequency divider 16 by L (L is an integer of 1 or more), and outputs a first local oscillation signal. The M divider 18 divides the frequency of the second local oscillation reference signal by M (M is an integer of 3 or more), and the N multiplier 19 multiplies the output frequency of the M divider 18 by N times ( N is an integer of 1 or more), and outputs a second local oscillation signal. The transmission antenna 8 irradiates a transmission signal to a target. Receiving antenna 9
Receives the reflected signal from the target and receives the signal (FIG. 12).
It corresponds to the curve b in (a). ) Is output. First
The even harmonic mixer 21a outputs an intermediate frequency signal having the sum and difference frequencies of the double frequency of the second local oscillation signal and the frequency of the reception signal. The first amplifier 11a power-amplifies the intermediate frequency signal. 2nd even harmonic mixer 21b
Outputs a video signal having the sum and difference frequencies of the double frequency of the first local oscillation signal and the frequency of the intermediate frequency signal (FIG. 1).
This corresponds to the curve c in 2 (b). ) Is output. The filter 13 filters the harmonic component of the video signal. The second amplifier 11b amplifies the video signal output from the filter 13. A / D converter 14
Converts the video signal output from the second amplifier 11b into a digital signal. The signal processing unit 15 receives the digitized video signal and derives a target distance and a relative speed. Thus, in the present embodiment, as compared with the conventional configuration, one intermediate frequency oscillator and one fundamental wave mixer 1 are provided.
Since the configuration can be omitted, the size, cost, and power consumption of the device can be reduced, and the mountability to a car or the like and mass productivity can be improved. Also, by using a plurality of even harmonic mixers 21, the noise figure of the receiving system can be further improved as compared with the third embodiment, and the distance performance of the FM-CW radar can be improved. Becomes possible.

However, the values of N, M, L and K cited here require the relationship of Equation 3.

[0036]

(Equation 3)

Embodiment 6 FIG. FIG. 7 is a block diagram of an FM-CW radar showing a sixth embodiment of the present invention, in which 6 is an oscillator, 7 is a directional coupler, 8 is a transmitting antenna, 9 is a receiving antenna, 11a and 11b. Is a first and a second amplifier, 12 is a distributor, 13 is a filter, 14
Is an A / D converter, 15 is a signal processor, 21a and 21b
Has a built-in anti-parallel diode pair in which two diodes of opposite polarities are connected in parallel, and outputs first and second signals having a frequency of the sum and difference between the frequency of the local oscillation signal and the frequency of the reception signal. The even harmonic mixer 23 is a frequency divider.

Next, the operation will be described. 7, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) emitted from a transmitting antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is A high frequency component, ± ΔF is a modulation frequency component.) The directional coupler 7 outputs a part of the output of the oscillator 6 as a transmission signal, and outputs the rest as a local oscillation reference signal. The four-frequency divider 23 divides the frequency of the local oscillation reference signal by four. The divider 12 distributes the power of the output of the ４ frequency divider 23 to power. The transmission antenna 8 irradiates a transmission signal to a target. The receiving antenna 9 is
Upon receiving the reflected signal from the target, the received signal (FIG. 12A)
Corresponds to curve b. ) Is output. The first even harmonic mixer 21a outputs an intermediate frequency signal having a frequency of the sum and difference between the double frequency of one output of the distributor 12 and the frequency of the received signal. The first amplifier 11a power-amplifies the intermediate frequency signal. 2nd even harmonic mixer 21
b outputs a video signal (corresponding to a curve c in FIG. 12B) having a sum and difference frequency between the double frequency of the other output of the frequency divider 12 and the frequency of the intermediate frequency signal. The filter 13 filters the harmonic component of the video signal. The second amplifier 11b includes the filter 1
3 is amplified. The A / D converter 14 digitally converts the video signal output from the second amplifier 11b. The signal processing unit 15 receives the digitized video signal and derives a target distance and a relative speed. As described above, in the present embodiment, one intermediate frequency oscillator and one fundamental wave mixer can be omitted as compared with the conventional configuration, and the frequency divider can be compared with the fifth embodiment. In addition, since the multiplier and the like can be omitted, the size, cost, and power consumption of the device can be reduced, and the mountability and mass productivity of an automobile or the like can be improved. Further, by using the even harmonic mixer 21, the noise figure of the receiving system is improved, the distance performance of the FM-CW radar can be improved, and accurate safety measures can be taken.

Embodiment 7 FIG. 8 is a block diagram of an FM-CW radar according to a seventh embodiment of the present invention. In the figure, reference numeral 6 denotes an oscillator having a built-in super step junction varactor diode, and reference numerals 7a and 7b denote first and second directional characteristics. A coupler, 8 is a transmitting antenna, 9 is a receiving antenna, 10a and 10b are first and second fundamental wave mixers, 11a and 11
b is the first and second amplifiers, 13 is a filter, 14 is A
/ D converter, 15 is a signal processing unit, 16 is a K frequency divider, 17
Is an L frequency multiplier, 18 is an M frequency divider, 19 is an N frequency multiplier, and 24 is an X frequency multiplier.

Next, the operation will be described. 8, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) emitted from a transmission antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is The high frequency component, ± ΔF is the modulation frequency component.)
A signal having a frequency of X is output. The X multiplier 24 multiplies the frequency of the output of the oscillator 6 by X. The first directional coupler 7a uses a part of the output of the X multiplier 24 as a transmission signal,
The rest is output as a local oscillation reference signal. Subsequent operations are the same as in the first embodiment. As described above, in the present embodiment, as compared with the conventional configuration, the configuration can be omitted by omitting one oscillator for the intermediate frequency signal and one fundamental wave mixer, so that the device can be reduced in size, cost and power consumption. It is possible to use electric power, and it is possible to improve the mountability on a car and the like and the mass productivity.

In a conventional FM-CW radar, when a high frequency band such as a millimeter wave band is used as a transmission signal, the frequency of the transmission signal is directly oscillated. Was getting worse,
By obtaining a transmission signal by multiplying the output of the oscillator 6 using the super step junction varactor diode by X, it is possible to improve the linearity. Therefore, S / N
Ratio can be prevented and the frequency can be prevented from being broadened.
It is possible to prevent the deterioration of the distance performance of the M-CW radar and the deterioration of the accuracy of the distance and the relative speed.

Embodiment 8 FIG. FIG. 9 is a block diagram of an FM-CW radar showing an eighth embodiment of the present invention, in which 6 is an oscillator, 7a and 7b are first and second directional couplers, 10a and 10b are 1st and 2nd fundamental wave mixers, 11a and 11b are 1st and 2nd amplifiers,
13 is a filter, 14 is an A / D converter, 15 is a signal processing unit, 16 is a K frequency divider, 17 is an L frequency multiplier, 18 is an M frequency divider, 19 is an N frequency multiplier, 25 is a transmission / reception switch, 26 is a transmitting / receiving antenna.

Next, the operation will be described. 9, an oscillator 6 corresponds to a high-frequency modulated signal (corresponding to a curve a in FIG. 12A) emitted from a transmitting antenna 8 to a target (omitted in the figure). The frequency is F _RF ± ΔF, and F _RF is A high frequency component, ± ΔF is a modulation frequency component.) The first directional coupler 7a and the second directional coupler 7b output a part of the output of the oscillator 6 as a transmission signal and output the rest as first and second local reference signals. The transmission / reception switch 23 guides the transmission signal to the transmission / reception antenna 24 and converts the reception signal from the transmission / reception antenna 24 to the first fundamental wave mixer 1.
Lead to 0a. The transmitting / receiving antenna 24 irradiates a target (not shown in the figure) with a transmission signal, receives a reflected wave from the target,
Output the received signal. Subsequent operations are the same as in the first embodiment. As described above, in the present embodiment, as compared with the conventional configuration, one intermediate frequency signal oscillator, one fundamental wave mixer, and one antenna can be omitted, so that the device can be reduced in size and inexpensive. Power consumption can be reduced, and the mountability and mass productivity of automobiles and the like can be improved.

[0044]

According to the FM-CW radar according to the first aspect of the present invention, the oscillator, the directional coupler, the transmitting and receiving antennas, and the K frequency dividing the frequency of the local oscillation signal by K and M are performed. And an M frequency divider (K and M are integers of 2 or more), an L frequency multiplier and an N frequency multiplier (L and N are integers of 1 or more) for multiplying the divided local signal by L and N. , A first fundamental wave mixer for receiving and converting the output of the N multiplier and a received signal, and a second fundamental mixer for performing frequency conversion based on the frequency of the signal output from the first fundamental wave mixer and the output frequency of the L multiplier. With the configuration including the wave mixer, the A / D converter, and the signal processing unit that obtains the distance to the target and the relative speed from the output of the A / D converter, the intermediate frequency is higher than that of the conventional configuration. Oscillator and one fundamental wave mixer can be omitted. Cost and power consumption become possible, thereby improving the mountability and productivity to an automobile or the like.

According to the second aspect of the present invention, the oscillator, the directional coupler, the transmitting and receiving antennas, the frequency divider for dividing the frequency of the local oscillation signal by two, the distributor, and the distributor A first fundamental wave mixer that receives one of the output and the received signal to perform frequency conversion, and a second fundamental wave mixer that performs frequency conversion based on the frequency of the output signal and the frequency of the other output signal of the distributor.
, An A / D converter, and a signal processing unit that obtains a distance and a relative speed to a target from the output of the A / D converter. One intermediate frequency oscillator and one fundamental wave mixer can be omitted, and a frequency divider, a multiplier and the like can be omitted as compared with the first embodiment, so that the device can be reduced in size, cost and power consumption. Is possible, and the mountability on a car or the like and the mass productivity can be improved.

According to the third aspect of the present invention, the oscillator, the directional coupler, the transmitting and receiving antennas, the K divider and the M divider for dividing the frequency of the local oscillation signal by K and M are provided. Container (K
, And M are integers of 3 or more), and an L multiplier and an N multiplier for L-multiplying and N-multiplying the divided local oscillation signal (L and N are 1 and 2).
An intermediate frequency signal having a built-in anti-parallel diode pair in which two diodes of opposite polarities are connected in parallel, and having the sum and difference frequencies of the double frequency of the output of the N multiplier and the frequency of the received signal. An A / D converter; an A / D converter; an even harmonic mixer for outputting a signal; an even harmonic mixer for converting the frequency of the intermediate frequency signal and the frequency of the output of the L multiplier;
A signal processing unit for obtaining the distance to the target and the relative speed from the output of the / D converter is provided, so that one intermediate frequency oscillator and one fundamental wave mixer are omitted as compared with the conventional configuration. Therefore, it is possible to reduce the size, cost, and power consumption of the device, and to improve the mountability and mass productivity in an automobile or the like. Further, by using an even harmonic mixer having a lower output noise level than the fundamental mixer, the noise figure of the receiving system can be reduced, and an appropriate safety measure can be taken.

According to the fourth aspect, the oscillator, the directional coupler, the transmitting and receiving antennas, the frequency divider for dividing the frequency of the local oscillation signal by three, and the output of the frequency divider for three And a built-in anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel, and an intermediate frequency having a frequency of the sum and difference between the frequency of the output of the distributor and the frequency of the received signal. An even harmonic mixer that outputs a signal,
A fundamental wave mixer for frequency-converting from the frequency of the intermediate frequency signal and the frequency of the other output of the distributor, an A / D converter, and signal processing for obtaining the distance and relative speed to a target from the output of the A / D converter With this configuration, one intermediate frequency oscillator and one fundamental wave mixer can be omitted as compared with the conventional configuration, and a frequency divider, a multiplier and the like can be omitted as compared with the third embodiment. Since it can be omitted, the size, cost and power consumption of the device can be reduced, and the mountability and mass productivity in an automobile or the like can be improved. Further, by using an even harmonic mixer having a lower output noise level than the fundamental mixer, the noise figure of the receiving system can be reduced, and an appropriate safety measure can be taken.

According to the fifth aspect of the present invention, the oscillator, the directional coupler, the transmitting and receiving antennas, the K divider and the M divider for dividing the frequency of the local oscillation signal by K and M are provided. Container (K
, And M are integers of 3 or more), and an L multiplier and an N multiplier for L-multiplying and N-multiplying the divided local oscillation signal (L and N are 1 and 2).
An intermediate frequency signal having a built-in anti-parallel diode pair in which two diodes of opposite polarities are connected in parallel, and having the sum and difference frequencies of the double frequency of the output of the N multiplier and the frequency of the received signal. And a video signal having a frequency of the sum and difference between the double frequency of the output of the L multiplier and the frequency of the intermediate frequency signal. 2 even harmonic mixer, an A / D converter, and a signal processing unit that obtains the distance to the target and the relative speed from the output of the A / D converter. As a result, one intermediate frequency oscillator and one fundamental wave mixer can be omitted, so that the device can be reduced in size, cost and power consumption can be reduced, and the mountability in a car or the like and the mass productivity can be improved. Further, the even harmonic mixer having a lower output noise level than the fundamental wave mixer is provided in two stages.
Therefore, the noise figure of the receiving system can be reduced, and an appropriate safety measure can be taken.

According to the sixth aspect of the invention, the oscillator, the directional coupler, the transmitting and receiving antennas, the frequency divider for dividing the frequency of the local oscillation signal by four, and the output of the frequency divider are divided by four. And an anti-parallel diode pair in which two diodes of opposite polarity are connected in parallel, and the sum and difference of the double frequency of one output of the distributor and the frequency of the output signal of the receiving antenna are built in. A first even harmonic mixer that outputs an intermediate frequency signal having a frequency, and an anti-parallel diode pair are built in, and the sum and difference frequencies of the double frequency of the other output of the distributor and the frequency of the intermediate frequency signal are determined. Having a second even harmonic mixer for outputting a video signal having the same, an A / D converter, and a signal processing unit for obtaining a distance to a target and a relative speed from an output of the A / D converter. , Medium compared to conventional configuration One oscillator of frequency and one fundamental wave mixer can be omitted, and a frequency divider, a multiplier and the like can be omitted as compared with the fifth embodiment, so that the device can be reduced in size, cost and power consumption. This makes it possible to improve the mountability on a car or the like and the mass productivity. Furthermore, by providing the even harmonic mixer having a lower output noise level than the fundamental mixer in two stages, the noise figure of the receiving system can be reduced and an appropriate safety measure can be taken.

According to the seventh aspect of the invention, an oscillator having a super step junction diode built therein, an X multiplier for multiplying the output frequency of the oscillator by X, a directional coupler, a transmitting and receiving antenna, a station, K that divides the frequency of the emitted signal by K and M
A frequency divider and an M frequency divider (K and M are integers of 2 or more) and an L frequency multiplier and an N frequency multiplier (L and N are integers of 1 or more) for multiplying the divided local signal by L and N times ), A first fundamental wave mixer for receiving and converting the output of the N-multiplier and the received signal, and converting the video signal from the output frequency of the first fundamental-wave mixer and the frequency of the output of the L-multiplier. With the configuration including the second fundamental wave mixer for outputting, the A / D converter, and the signal processing unit for obtaining the distance and the relative speed to the target from the output of the A / D converter, the conventional configuration is achieved. Compared to,
Since one intermediate frequency oscillator and one fundamental wave mixer can be omitted, it is possible to reduce the size, cost, and power consumption of the device, and to improve the mountability and mass productivity in automobiles and the like. . Further, the use of an oscillator having a built-in super-step junction diode can improve the linearity, and can take appropriate safety measures.

According to the eighth invention, the oscillator, the directional coupler, the transmission / reception switch, the transmission / reception antenna, the K frequency divider for dividing the frequency of the local oscillation signal by K and M, and An M frequency divider (K and M are integers of 2 or more), an L multiplier and an N frequency multiplier (L and N are integers of 1 or more) for multiplying the divided local signal by L and N, A first fundamental wave mixer for receiving and converting the output of the multiplier and the received signal, and a second fundamental frequency mixer for converting the output frequency of the first fundamental wave mixer and the output frequency of the L multiplier to output a video signal And a signal processing unit that obtains the distance to the target and the relative speed from the output of the A / D converter, as compared with the conventional configuration. Embodiment 1 can be configured by omitting one intermediate frequency oscillator and one fundamental wave mixer. Can be omitted antenna 1 month compared, the size of the apparatus enables lower cost and power consumption, can improve the mountability and productivity to an automobile or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing Embodiment 1 of an FM-CW radar according to the present invention.

FIG. 2 is a diagram showing a second embodiment of the FM-CW radar according to the present invention.

FIG. 3 is a diagram showing a third embodiment of the FM-CW radar according to the present invention;

FIG. 4 is a diagram illustrating an example of output noise levels of a fundamental wave mixer and an even harmonic mixer.

FIG. 5 is a diagram showing a fourth embodiment of the FM-CW radar according to the present invention.

FIG. 6 is a diagram showing a fifth embodiment of the FM-CW radar according to the present invention;

FIG. 7 is a diagram showing a sixth embodiment of the FM-CW radar according to the present invention;

FIG. 8 is a diagram showing a seventh embodiment of the FM-CW radar according to the present invention;

FIG. 9 is a diagram showing an eighth embodiment of the FM-CW radar according to the present invention.

FIG. 10 is a diagram showing a use situation of an FM-CW radar.

FIG. 11 is a diagram showing a conventional FM-CW radar.

FIG. 12 is a diagram illustrating an operation principle of the FM-CW radar.

FIG. 13 is a diagram illustrating a relationship between linearity and target detection accuracy.

[Explanation of symbols]

1 road, 2a first vehicle, 2b second vehicle, 3
FM-CW radar, 4 obstacles, 5 humans, 6 oscillators,
6a first oscillator, 6b second oscillator, 7 directional coupler, 7a first directional coupler, 7b second directional coupler, 8 transmitting antenna, 9 receiving antenna, 10
Fundamental wave mixer, 10a first fundamental wave mixer, 10b
2nd fundamental wave mixer, 10c 3rd fundamental wave mixer, 1
1a 1st amplifier, 11b 2nd amplifier, 12 divider, 13 filter, 14A / D converter, 15 signal processing unit, 16K divider, 17L multiplier, 18M divider, 19N multiplier , 202 frequency divider, 21 even harmonic mixer, 21a first even harmonic mixer, 21b second even harmonic mixer, 223 frequency divider, 234 frequency divider, 24
X multiplier, 25 transmission / reception switch, 26 transmission / reception antenna.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Teruo Furuya 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (8)

[Claims] An oscillator for generating a high-frequency modulated signal, a directional coupler for outputting two local signals and a transmission signal from the output of the oscillator, a transmission antenna for irradiating the transmission signal to a target, and the target , A K frequency divider for dividing the frequency of the one local signal by K (K is an integer of 2 or more), and multiplying the output frequency of the K frequency divider by L times ( L is an integer of 1 or more), an M frequency divider that divides the frequency of the other local signal by M (M is an integer of 2 or more), and an output of the M frequency divider An N-multiplier for multiplying the frequency by N times (N is an integer of 1 or more), a first fundamental wave mixer for receiving the output of the N-multiplier and the output of the receiving antenna, and converting the frequency; The frequency is determined from the frequency of the signal output from the fundamental wave mixer and the frequency of the signal output from the L multiplier. A second fundamental wave mixer for converting a wave number to output a video signal, an A / D converter for digitally converting the video signal, and obtaining a distance and a relative speed to the target from an output of the A / D converter An FM-CW radar comprising a signal processing unit. 2. An oscillator for generating a high-frequency modulation signal, a directional coupler for outputting a local oscillation signal and a transmission signal from an output of the oscillator, a transmission antenna for irradiating the transmission signal to a target, A receiving antenna for receiving the reflected signal, a frequency divider for dividing the frequency of the local oscillation signal by 2, a power divider for dividing the output of the frequency divider, and an output of one of the dividers and the receiver A first fundamental wave mixer for receiving the output of the antenna and converting the frequency; and converting the frequency from the frequency of the signal output from the first fundamental wave mixer and the frequency of the other local signal output from the distributor to produce a video. A second fundamental wave mixer for outputting a signal, an A / D converter for digitally converting the video signal, and a signal processing unit for obtaining a distance and a relative speed to the target from an output of the A / D converter. Features FM-CW radar. 3. An oscillator for generating a high-frequency modulation signal, a directional coupler for outputting two local signals and a transmission signal from the output of the oscillator, a transmission antenna for irradiating the transmission signal to a target, and the target , A K frequency divider for dividing the frequency of the one local signal by K (K is an integer of 3 or more), and multiplying the output frequency of the K frequency divider by L times ( L is an integer of 1 or more), an M frequency divider for dividing the frequency of the other local signal by M (M is an integer of 3 or more), and an output of the M frequency divider An N multiplier for multiplying the frequency by N times (N is an integer of 1 or more) and an anti-parallel diode pair in which two diodes of opposite polarities are connected in parallel are incorporated. Intermediate with sum and difference frequencies from the output signal frequency of the receiving antenna An even harmonic mixer for outputting a frequency signal, a fundamental wave mixer for converting the frequency of the intermediate frequency signal and the frequency of the output of the L multiplier and outputting a video signal, and an A / A for digitally converting the video signal.
An FM-CW radar comprising: a D converter; and a signal processing unit for obtaining a distance and a relative speed to the target from an output of the A / D converter. 4. An oscillator for generating a high-frequency modulation signal, a directional coupler for outputting a local oscillation signal and a transmission signal from the output of the oscillator, a transmission antenna for irradiating the transmission signal to a target, A receiving antenna for receiving the reflected signal; a three-frequency divider for dividing the frequency of the local signal by three; a divider for dividing the output of the three-frequency divider into power;
An anti-parallel diode pair in which three diodes are connected in parallel, and an even-numbered signal for outputting an intermediate frequency signal having a frequency of a sum and a difference between a double frequency of one output of the distributor and a frequency of an output signal of the receiving antenna. A harmonic mixer, a fundamental wave mixer for converting the frequency of the intermediate frequency signal and the frequency of the other output of the distributor and outputting a video signal, and an A for digitally converting the video signal
An FM-CW radar comprising: a digital-to-analog (D / D) converter; and a signal processing unit that obtains a distance and a relative speed to the target from an output of the A / D converter. 5. An oscillator for generating a high-frequency modulation signal, a directional coupler for outputting two local oscillation signals and a transmission signal from the output of the oscillator, a transmission antenna for irradiating the transmission signal to a target, and the target , A K frequency divider for dividing the frequency of the one local signal by K (K is an integer of 3 or more), and multiplying the output frequency of the K frequency divider by L times ( L is an integer of 1 or more), an M frequency divider for dividing the frequency of the other local signal by M (M is an integer of 3 or more), and an output of the M frequency divider An N multiplier for multiplying the frequency by N times (N is an integer of 1 or more) and an anti-parallel diode pair in which two diodes of opposite polarities are connected in parallel are incorporated. Intermediate with sum and difference frequencies from the output signal frequency of the receiving antenna A video having a first even harmonic mixer for outputting a frequency signal and the anti-parallel diode pair, and having a frequency of a sum and a difference between a double frequency of the output of the L multiplier and the frequency of the intermediate frequency signal A second even harmonic mixer for outputting a signal, an A / D converter for digitally converting the video signal, and a signal processing unit for obtaining a distance and a relative speed to the target from an output of the A / D converter. An FM-CW radar comprising: 6. An oscillator for generating a high-frequency modulation signal, a directional coupler for outputting a local oscillation signal and a transmission signal from an output of the oscillator, a transmission antenna for irradiating the transmission signal to a target, A receiving antenna for receiving the reflected signal, a frequency divider for dividing the frequency of the local oscillation signal by four, a power divider for dividing the output of the frequency divider for four,
An anti-parallel diode pair in which three diodes are connected in parallel, and an intermediate frequency signal having a frequency of a sum and a difference between a double frequency of one output of the distributor and a frequency of an output signal of the receiving antenna is output. 1 even harmonic mixer and the above anti-parallel diode pair
A second even harmonic mixer for outputting a video signal having a frequency of a sum and difference between a frequency twice as high as the other output of the distributor and the frequency of the intermediate frequency signal, and an A / A for digitally converting the video signal; An FM-CW radar comprising: a D converter; and a signal processing unit that obtains a distance and a relative speed to the target from an output of the A / D converter. 7. An oscillator having a built-in super step junction diode and generating a low frequency modulation signal, and an X multiplier for multiplying the frequency of the low frequency modulation signal output from the oscillator by X times (X is an integer of 1 or more) ) To obtain a high-frequency modulated signal.
M-CW radar. 8. The apparatus according to claim 1, wherein an antenna used for transmission and reception is shared by one antenna.
Any of the FM-CW radars described.