JP2570965B2 - Radio wave receiver - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave receiving apparatus, and more particularly to a function of removing direct waves from a radar installed in the same area and unnecessary signals (clutter) due to reflected waves from the surrounding ground surface and buildings. The present invention relates to a radio wave receiving device having

[0002]

2. Description of the Related Art Conventionally, this type of radio wave receiving apparatus has a configuration as shown in FIG.
A receiving unit 2 for amplifying and detecting the F signal, and a pulse which receives a timing signal synchronized with the transmission of a radar installed in the same area, and extends this timing signal by a predetermined time during which the radar transmission time and the reflected wave exist. It has a decompression circuit 5, a switch circuit 3 that is turned on and off by an output signal of the pulse decompression circuit, and a pulse detection circuit 4 that detects a pulse.
From the received signal, reflected waves from the ground surface, buildings, and the like during and after radar transmission are removed.

FIG. 4 shows waveforms at various parts of the conventional radio wave receiving apparatus. (A) is a transmission wave of a nearby radar, (b) is a radar transmission timing signal T1, (c) is a pulse expansion circuit output T2, (d) is a reception signal T3, (e) is a switch circuit output signal T5, (f) ) Indicate the pulse detection circuit output T6.

[0004]

In this conventional radio wave receiving apparatus, as shown in FIG. 4, a transmission time and a predetermined constant time switch in which a reflected wave is present in synchronization with the transmission of a radar installed in the same area. Since the circuit 3 is turned off, all the received signals cannot be detected during this period.
For this reason, it is impossible to detect an important signal received during a period in which the switch circuit 3 is turned off, for example, a radio signal emitted by a suddenly appearing mobile object or an important signal of another radar or the like which has started transmission suddenly. There is a problem.

An object of the present invention is to improve the signal detection probability by shortening the time for turning off a received signal.

[0006]

According to the present invention, there is provided a radio wave receiving apparatus for amplifying and detecting an RF signal received via an antenna and outputting the signal in synchronization with a radar transmission timing.
Extend radar transmission timing signal to radar transmission pulse width.
The length of the pulse expansion circuit and the output of the pulse expansion circuit are used to convert the received signal, which is the output of the receiver, to the radar transmission pulse width.
A switch circuit that interrupts only the interval and the radar transmission timing signal, and only for a certain period of time when the radar reflected wave exists
Signal detection level is larger than radar reflected signal level
And a signal detection circuit for detecting a received signal exceeding a signal detection level determined by the detection reference signal generation circuit.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. This radio wave receiving apparatus includes an antenna 1 and an antenna 1
A receiver 2 for amplifying and detecting the RF signal received via the
A pulse expansion circuit 5 for expanding a pulse width in response to a radar transmission timing signal, a switch circuit 3 for interrupting a reception signal output from the reception unit 2 by an output of the pulse expansion circuit 5, and a radar transmission timing signal. A detection reference signal generation circuit 6 for raising the signal detection level of the signal detection circuit 4 by a predetermined set value for a predetermined time, and a reception signal exceeding a signal detection level determined by the detection reference signal generation circuit 6 is detected. And a signal detection circuit 4.

FIGS. 2A and 2B are waveform diagrams showing the operation of this embodiment. FIG. 2A shows a transmission wave of a nearby radar, FIG. 2B shows a radar transmission timing signal T1, and FIG.
2, (d) is a detection reference signal generation circuit output T4 and a reception signal T3, (e) is a switch circuit output signal T5, (f)
Indicates a signal detection circuit output signal T6.

Next, the operation of this embodiment will be described with reference to FIGS.

[0011] The receiving unit 2 receives the R
It performs amplification detection of the F signal, and outputs the received signal to the switch circuit 3. The radar transmission timing signal T1 output in synchronization with the radar transmission timing is expanded by the pulse expansion circuit 5 to the radar transmission pulse width and input to the switch circuit 3. In the switch circuit 3, the switch is turned off by the signal from the pulse expansion circuit 5 for the time corresponding to the radar transmission pulse width. As a result, as shown by the switch circuit output signal T5 in FIG. 2, the direct wave from the radar is removed from the reception signal output from the reception unit 2, and this signal is input to the signal detection circuit 4.

When the radar transmission timing signal T1 is input, the detection reference signal generation circuit 6 outputs the detection reference signal generation circuit output T of FIG.
As shown in FIG. 4, a signal larger than a preset signal level of the reflected wave of the radar is output. The signal detection circuit 4 compares the signal from the detection reference signal generation circuit 6 with the reception signal, and performs signal detection when the reception signal is larger than the signal from the detection reference signal generation circuit 6. As a result, only extraneous waves are detected.

According to the conventional method, the reception signal is turned off including the period in which the direct wave and the reflected wave of the radar exist, but according to this method, the reception signal is turned off only during the period in which the direct wave exists. Therefore, the detection probability of a foreign signal can be improved.

[0014]

As described above, the radio wave receiving apparatus according to the present invention comprises a receiving section for amplifying and detecting an RF signal received via an antenna, and a pulse extending section for extending a pulse width in response to a radar transmission timing signal. Circuit, a switch circuit that cuts off the reception signal output from the reception unit by the output of the pulse decompression circuit, and a signal detection level of the signal detection circuit that is higher by a predetermined set value for a certain period of time after receiving the radar transmission timing signal. And a signal detection circuit that detects a received signal exceeding a signal detection level determined by the detection reference signal generation circuit, thereby reducing the time for turning off the received signal, Can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a waveform chart showing the operation of the embodiment.

FIG. 3 is a block diagram illustrating an example of a conventional radio wave receiving device.

FIG. 4 is a waveform chart showing the operation of the conventional radio wave receiving device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 antenna 2 reception unit 3 switch circuit 4 signal detection circuit 5 pulse expansion circuit 6 detection reference signal generation circuit T1 radar transmission timing signal T2 pulse expansion circuit output signal T3 reception signal T4 detection reference signal generation circuit output signal T5 switch circuit output signal T6 Signal detection circuit output signal t1 Period in which radar wave exists

Claims (1)

(57) [Claims] A receiver for amplifying and detecting an RF signal received via an antenna, and a radar transmission output in synchronization with a radar transmission timing.
A pulse expansion circuit that extends the transmission timing signal to the radar transmission pulse width, a switch circuit that cuts off the reception signal output from the receiver by the output of the pulse expansion circuit for the duration of the radar transmission pulse width, and radar transmission timing Received signal and radar reflected wave
The signal detection level for a certain period of time
1. A radio wave receiving apparatus comprising: a detection reference signal generation circuit for increasing a signal level higher than a signal level; and a signal detection circuit for detecting a reception signal exceeding a signal detection level determined by the detection reference signal generation circuit.