JPH0531945B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse radar device.

[Conventional technology]

As an example of the prior art, a block diagram of a commonly used radar device is shown in FIG. In the figure, 1
is the antenna, 2 is the transmitter/receiver, 3 is the second frequency converter, 4 is the IF amplifier, 5 is the second DDL (chirp
Direction: up chirp), 6 is the detector, 7 is the signal processor,
8 is a local signal generator, 9 is a power amplifier, 10 is a first frequency converter, 11 is a gate circuit, 12 is a first DDL (chirp direction: up chirp), 13 is an impulse signal generator, 14 is a transmission pulse generator, 15
is a reference signal generator, and 17 is a third frequency converter.

A signal with the same frequency (f _I ) as the IF signal is sent from the reference signal generator 15 to the impulse signal generator 13,
As an impulse signal by the impulse timing signal sent from the transmission pulse generator 14,
input to the first DDL 12 whose chirp direction is up,
Outputs a frequency modulated expanded pulse signal. The frequency modulated expanded pulse signal is passed through the gate circuit 11 by the transmission pulse width in response to the transmission timing signal sent from the transmission pulse generator 14, and the first
is sent to the frequency converter 10 of. At the same time, the local signal ( _L ) sent from the local signal generator 8 and the intermediate frequency signal sent from the reference signal generator 15 are
A third frequency converter 17 performs frequency addition ( _fL + 2f _I ) of signals with a frequency (2f _I ) corresponding to twice the frequency,
The first frequency converter 10 converts the transmission pulse signal and frequency (subtraction/f _L +2f _I −f _I = f _L + f _I = f _R )
The transmission frequency is set to down chirp in the chirp direction, the power is amplified by the power amplifier 9, and the signal is radiated into the air through the transmitter/receiver switch 2 and the antenna 1.
The signal that hits the target and becomes a reflected signal passes through the antenna 1 and the transmitter/receiver switch 2 as a received signal, and is frequency-converted by the signal from the local oscillator 8 at the second frequency converter 3 to become an IF signal. This IF signal is amplified by IF amplifier 4, and the chirp direction is up chirp.
undergoes pulse compression processing in the second DDL5, which is
The signal is detected by a detector 6 and sent to a signal processor 7 as a video signal.

[Problem that the invention seeks to solve]

In such a conventional radar device, the only way to evaluate the pulse compression function in the IF frequency band f _I is to pass through the RF frequency band (frequency band for transmitting and receiving, f _R ). The reason is that the first DDL that generates the frequency modulation expansion signal and the second DDL that performs pulse compression processing are both the same.
This is because the chirp direction is used.

This is because, considering the receiving system's waylining filter separately, if the chirp direction is made the same, there is an advantage that the first and second DDLs can use exactly the same thing.

However, from the viewpoint of ease of testing, it is a problem that test signals in the IF frequency band cannot be used.

At the same time, by providing the third frequency converter 17, the chirp direction can be changed by the first frequency converter 10.
There is also the problem that it becomes necessary to perform an operation of converting an up chirp to a down chirp, which increases the amount of hardware.

The present invention seeks to overcome the problems of the prior art.

[Means for solving the problem] The chirp directions of the first DDL that generates the frequency modulation expansion signal and the second DDL that performs pulse compression processing are made up chirp and down chirp, respectively, and at the same time, the output of the gate circuit is A splitter was installed to make it possible to extract test signals in the IF frequency band.

[Effect]

By the above means, the test signal in the IF frequency band is
By inputting it to the input of the IF amplifier or the input of the second DDL, pulse compression tests can be performed without passing through the RF band.

At the same time, since it is no longer necessary to invert the chirp direction in the first frequency converter, the third frequency converter is no longer necessary, and hardware can be reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram, in which 1 to 15 are exactly the same as the conventional device (however, the chirp direction of the second DDL of 5 is down chirp), and 1
6 is a distributor.

A signal with the same frequency (f _I ) as the IF signal is sent from the reference signal generator 15 to the impulse signal generator 13,
chirp as an impulse signal by the impulse timing signal sent from the transmission pulse generator 14
The signal is input to the first DDL 12 whose direction is up, and a frequency modulated expanded pulse signal is output. The frequency modulated expanded pulse signal is transmitted to the gate circuit 1 by a transmission timing signal sent from the pulse generator 14.
1, the signal passes through only the width of the transmission pulse, and is sent to the first frequency converter 10 through the distributor 16. The local signal sent from the local signal generator 8 is frequency-converted to the transmission frequency (addition/f _L + f _I = f _R ), power amplified by the power amplifier 9, and radiated into the air through the transmitter/receiver switch 2 and antenna 1. be done. The signal that hits the target and becomes a reflected signal passes through the antenna 11 and the transmitter/receiver switch 2 as a received signal, and is frequency-converted by the signal from the local signal generator 8 at the second frequency converter 3 to become an IF signal. This IF signal is amplified by an IF amplifier 4, subjected to pulse compression processing by a second DDL 5 whose chirp direction is down chirp, detected by a detector 6, and sent to a signal processor 7 as a video signal.

During testing, the other output signal of the distributor 16 is
IF amplifier 4 or the second
It can be added to the input of DDL5.

〔Effect of the invention〕

In the present invention, as described above, when testing the IF frequency band, the other output signal of the divider 16 can be input to the IF amplifier 4 or the second DDL 5 as a test signal.

At the same time, since the signal from the local signal generator 8 can be used for the first frequency converter 10, the third frequency converter 17, which is in the conventional configuration, is not required, and the hardware can be reduced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a radar device showing an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional radar device. 1 is an antenna, 2 is a transmission/reception switch, 3 is a second frequency converter, 4 is an IF amplifier, 5 is a second DDL,
6 is a wave detector, 7 is a signal processor, 8 is a local signal generator, 9 is a power amplifier, 10 is a first frequency converter, 11 is a gate circuit, 12 is a first DDL, 1
3 is an impulse signal generator, 14 is a transmission pulse generator, 15 is a reference signal generator, 16 is a distributor, 1
7 is a third frequency converter. Note that the same or corresponding parts in the figures are indicated by the same reference numerals.

Claims (1)

[Claims] 1. A reference signal generator that generates the same frequency as the radar IF signal, a transmission pulse generator that generates transmission timing and impulse timing pulses, and an impulse signal that receives the above reference signal and impulse timing signal and generates an impulse signal. a first pulse signal whose chirp direction is up-chip, which receives the output signal of the impulse signal generator and generates a frequency-modulated expanded pulse signal;
DDL (abbreviation for Dispersive Delay)
Line), a gate signal that gates the output signal of the first DDL with the transmission pulse signal to give the pulse width of the transmission pulse signal, and inputs the output signal of the gate circuit through a distributor, a first frequency converter that converts the output signal of the gate circuit to a transmission frequency using a signal from a local signal generator; a power amplifier that power amplifies the output of the first frequency converter; a transmitting/receiving switch that switches the received signal; an antenna that emits the transmitted signal and receives the received signal; a second frequency converter that receives the signal from the local signal generator and converts the frequency of the received signal; an IF amplifier that amplifies the output of the frequency converter; a second DDL whose chirp direction is down chirp for pulse-compressing the received signal amplified by this IF amplifier;
a detector that detects the output of the DDL and converts it into a video signal; a signal processor that receives the video signal and performs signal processing; and inputs the output signal of the gate circuit to the first frequency conversion circuit; for
A radar device comprising a distributor for inputting an IF signal to the IF amplifier or the second DDL.