JPH1039001A - Radar receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shield effectively unrequired signals from an antenna when an automatical noise level control circuit is activated, and to enhance the probability of reception system gain setting. SOLUTION: This embodiment comprises: an antenna 1 for gathering reflection waves from a target; a RF(radio frequency) front end 2 for amplifying RF signals from the antenna 1 and converting the RF signals into IF (intermediate frequency) signals; an IF amplifier 6 for amplifying output signals of the RF front end 2; an automatical noise lever control circuit 7 for making constant a gain of a reception system circuit and playing a roll for preventing signals noise level variations; and a mechanical shutter 9 for shielding the RF signals from the antenna 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic noise level control circuit (Automatic Noise Level).
ling, hereafter referred to as ANL circuit)
The present invention relates to a radar receiver configured to effectively block unnecessary signals input from an antenna.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional apparatus of this type. In the figure, reference numeral 1 denotes an antenna for collecting reflected waves from a target (not shown), and 2 denotes an RF from the antenna 1.
Amplify the signal and IF (Intermediate Fr)
RF (Radio F)
frequency) a front end, 3 an RF low noise amplifier for amplifying an RF signal from the antenna 1 in the RF front end 2, 4 a mixer constituting the RF front end 2, and 5 a local signal to the mixer 4. A local signal generator, 6 is an IF amplifier for amplifying the signal from the RF front end 2, and 7 is an ANL circuit (Automatic Noise L) which keeps the gain of a receiving system circuit and prevents signal noise level fluctuation.
and 8 is a power supply to the RF low noise amplifier 3.

Next, the operation will be described. The RF reception signal collected by the antenna 1 is input to the RF front end 2. Here, the signal is amplified and IF-converted, and is again amplified by the IF amplifier 6 connected to the output side. However, since the performance of electric components and the like changes depending on the temperature, the gain of the receiving system fluctuates, and the noise level of the signal fluctuates. The ANL circuit 7 connected to the output side of the IF amplifier 6 prevents this fluctuation.

[0004]

The above-mentioned conventional radar receiver has the following problems. That is, ANL noise is applied to reduce tracking sensitivity fluctuations or tracking errors due to signal level fluctuations.
GC (Automatic Gain Contro)
l) Voltage and STC (Sensitivity) applied in search mode to prevent receiver saturation
AGC voltage and STC during the ANL noise detection time so as not to fluctuate with the Time Control voltage.
The voltage is kept at 0V. Therefore, if strong jamming occurs during this detection, the AGC voltage and ST
Since the C voltage becomes a value larger than 0 V and the ANL circuit cannot detect only the normal reception noise, the reception system gain setting is incorrect.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a radar receiver for effectively blocking unnecessary signals received by an antenna when an ANL circuit is operating.

[0006]

In the first invention, the influence of unnecessary signals such as jamming signals and clutter signals is minimized by cutting off the RF signal from the antenna when the ANL circuit is operating. .

In the second invention, R
By cutting off the power supply for applying a voltage to the F signal and the RF low-noise amplifier constituting the RF front end when the ANL circuit is operated, the influence of unnecessary signals such as jamming signals and clutter signals is minimized. .

[0008] In the third invention, R
The effect of unnecessary signals such as jamming signals and clutter signals is minimized by cutting off the F signal when the ANL circuit is activated.

According to the fourth aspect of the present invention, R
By cutting off the F signal and the local signal to the mixer constituting the RF front end when the ANL circuit is activated, the influence of unnecessary signals such as a jamming signal and a clutter signal is minimized.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a diagram showing a first embodiment of the present invention. In FIG. 1, 1 to 8 are the same as those shown in FIG. 9 is a mechanical shutter for turning on and off the RF signal from the antenna, and L is a
An ANL operation signal indicating that the NL circuit 7 is operating.

Next, the operation will be described. ANL circuit 7
Is activated, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 are transmitted to the RF front end 2,
Input to the ANL circuit 7 after passing through the IF amplifier 6 to prevent an incorrect gain setting due to the inability to detect only normal reception noise, thereby enabling accurate automatic noise level control. . That is, the AN from the ANL circuit 7
The mechanical shutter 9 is closed by the L operation signal L to cut off the RF signal. Therefore, the unnecessary signal is greatly suppressed, and the ANL circuit 7 can detect only the noise generated by the receiving system.

Embodiment 2 FIG. FIG. 2 shows a second embodiment of the present invention. In FIG. 2, 1 to 8 are the same as those shown in FIG. 9 is a mechanical shutter for turning on and off the RF signal from the antenna, S is a switch for turning on and off the power to the RF low noise amplifier 3, and L is an ANL operation for notifying the mechanical shutter 9 and the switch S that the ANL circuit 7 is operating. Signal.

Next, the operation will be described. ANL circuit 7
When the antenna operates, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 are transmitted to the RF front end 2.
Input to the ANL circuit 7 after passing through the IF amplifier 6 to prevent an incorrect gain setting due to the inability to detect only normal reception noise, thereby enabling accurate automatic noise level control. . That is, the AN from the ANL circuit 7
The mechanical shutter 9 is closed by the L operation signal L, the switch S is turned off, and the RF signal and the RF low noise amplifier 3 are turned off.
To cut off the voltage to. Therefore, the unnecessary signal is greatly suppressed, and the ANL circuit 7 can detect only the noise generated by the receiving system.

Embodiment 3 FIG. 3 shows a third embodiment of the present invention. In FIG. 3, 1 to 8 are the same as those shown in FIG. 9 is a mechanical shutter for turning on and off the RF signal from the antenna, S is a switch for turning on and off the RF signal output from the mechanical shutter,
L is an ANL operation signal for notifying the mechanical shutter 9 and the switch S that the ANL circuit 7 is operating.

Next, the operation will be described. ANL circuit 7
When the antenna operates, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 are transmitted to the RF front end 2.
Input to the ANL circuit 7 after passing through the IF amplifier 6 to prevent an incorrect gain setting due to the inability to detect only normal reception noise, thereby enabling accurate automatic noise level control. . That is, the AN from the ANL circuit 7
The mechanical shutter 9 is closed by the L operation signal L, the switch S is turned off, and the RF signal is cut off. Therefore, the unnecessary signal is greatly suppressed, and the ANL circuit 7
Only the noise generated by the receiving system can be sensed.

Embodiment 4 FIG. 4 shows a fourth embodiment of the present invention. In FIG. 4, 1 to 8 are the same as those shown in FIG. 9 is a mechanical shutter for turning on and off the RF signal from the antenna, S is a switch for turning on and off the local signal to the mixer 4, and L is an ANL operation signal for notifying the mechanical shutter 9 and the switch S that the ANL circuit 7 is operating. is there.

Next, the operation will be described. ANL circuit 7
When the antenna operates, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 are transmitted to the RF front end 2.
Input to the ANL circuit 7 after passing through the IF amplifier 6 to prevent an incorrect gain setting due to the inability to detect only normal reception noise, thereby enabling accurate automatic noise level control. . That is, the AN from the ANL circuit 7
The mechanical shutter 9 is closed by the L operation signal L, the switch S is turned off, and the RF signal and the local signal from the local signal generator 5 to the mixer 4 are cut off. For that reason,
The unnecessary signal is greatly suppressed, and the ANL circuit 7 can detect only noise generated by the receiving system.

[0018]

As described above, according to the present invention, unnecessary signals such as a jamming signal when the ANL circuit operates can be ignored as compared with the conventional radar receiver. Therefore, there is an effect that the ANL circuit is properly operated to improve the setting accuracy of the reception system gain.

[Brief description of the drawings]

FIG. 1 is a block diagram of a radar transceiver according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram of a radar transceiver according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a radar transceiver according to Embodiment 3 of the present invention.

FIG. 4 is a block diagram of a radar transceiver according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram of a conventional radar receiver.

[Explanation of symbols]

1 antenna, 2 RF front end, 3 RF low noise amplifier, 4 mixer, 5 local signal generator, 6
IF amplifier, 7 ANL circuit, 8 power supply, 9 mechanical shutter, S switch, LANL operation signal.

Claims (4)

[Claims] An antenna for collecting reflected waves from a target;
RF (Radio Frequency) from the antenna
cy) amplify the signal and IF (Intermedia)
an RF front end for converting the signal into a signal (te Frequency), an IF amplifier for amplifying the output signal of the RF front end, and an output connected to the amplifier to prevent the reception gain from fluctuating and prevent the signal noise level from fluctuating. An automatic noise level control circuit, a power supply for applying a voltage to an RF low noise amplifier constituting the RF front end, a local signal generator for supplying a local signal to a mixer constituting the front end, and a front end from the antenna. And a mechanical shutter for turning on and off the RF signal to the radar. 2. An antenna for collecting reflected waves from a target,
RF (Radio Frequency) from the antenna
cy) amplify the signal and IF (Intermedia)
an RF front end for converting the signal into a signal (te Frequency), an IF amplifier for amplifying the output signal of the RF front end, and an output connected to the amplifier to prevent the reception gain from fluctuating and prevent the signal noise level from fluctuating. An automatic noise level control circuit, a power supply for applying a voltage to an RF low noise amplifier constituting the RF front end, a local signal generator for supplying a local signal to a mixer constituting the front end, and a front end from the antenna. A radar receiver comprising: a mechanical shutter for turning on / off an RF signal to / from a power supply; and a switch for turning on / off power to an RF low-noise amplifier in the RF front end. 3. An antenna for collecting reflected waves from a target,
RF (Radio Frequency) from the antenna
cy) amplify the signal and IF (Intermedia)
an RF front end for converting the signal into a signal (te Frequency), an IF amplifier for amplifying the output signal of the RF front end, and an output connected to the amplifier to prevent the reception gain from fluctuating and prevent the signal noise level from fluctuating. An automatic noise level control circuit, a power supply for applying a voltage to an RF low noise amplifier constituting the RF front end, a local signal generator for supplying a local signal to a mixer constituting the front end, and a front end from the antenna. 1. A radar receiver comprising: a mechanical shutter for turning on / off an RF signal to a front end; and an RF switch located behind the mechanical shutter for turning on / off an RF signal to a front end. 4. An antenna for collecting reflected waves from a target,
RF (Radio Frequency) from the antenna
cy) amplify the signal and IF (Intermedia)
an RF front end for converting the signal into a signal (te Frequency), an IF amplifier for amplifying the output signal of the RF front end, and an output connected to the amplifier to prevent the reception gain from fluctuating and prevent the signal noise level from fluctuating. An automatic noise level control circuit, a power supply for applying a voltage to an RF low noise amplifier constituting the RF front end, a local signal generator for supplying a local signal to a mixer constituting the front end, and a front end from the antenna. A mechanical shutter for turning on / off an RF signal to the front end and a switch for turning on / off a local signal to the front end.