JP2001159676A - Radar receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve wrong gain setting of a receiving system caused from that an unwanted signal is detected and then just only normal receiving noise cannot be sensed when a strong jamming from an antenna is inputted in operation of an automatic noise level control circuit. SOLUTION: The receiver arranges a branch circuit and termination between the antenna and a RF(Radio Frequency) front end to effectively transmit the unwanted signal from the antenna to the other and cut off an input to the RF front end in the operation of the automatic noise level control circuit.

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).
The present invention relates to a radar receiver configured to effectively block unnecessary signals obtained via an antenna when a ling (hereinafter, referred to as an ANL circuit) operates.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a diagram illustrating a conventional radar receiver disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-15095.
In the figure, 1 is an antenna for collecting reflected waves from a target (not shown), and 2 is an RF (Radio
Frequency (Frequency) signal and IF (Inte
RF front end, which converts the signal into an R.mediate Frequency signal, and 3 is the RF front end.
An RF low-noise amplifier for amplifying an RF signal from the antenna 1 therein, a mixer 4 constituting the RF front end 2, a local signal generator 5 for providing a local signal to the mixer 4, and a reference numeral 6 for the RF front end 2 An IF amplifier 7 for amplifying the signal from the ANL circuit (Automatic Noise Levelin) which keeps the gain of the receiving system circuit constant and prevents signal noise level fluctuation.
g) and 8 are power supplies 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 converted into an IF, and is amplified again 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 T) applied in search mode to prevent receiver saturation
ALC voltage and STC during the ANL noise detection time so as not to fluctuate due to the
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, the ANL circuit cannot sense only normal reception noise.
Incorrect reception system gain setting.

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

[0006]

In the radar receiver according to the first invention, when the ANL circuit is activated, the RF signal input from the antenna to the RF front end is controlled by branching off the branching circuit to the other side to cut off the RF signal. In addition, the influence of unnecessary signals such as a jamming signal and a clutter signal is minimized.

In the radar receiver of the second invention, A
When the NL circuit is activated, the RF signal input from the antenna to the RF front end is controlled by the demultiplexing circuit to be branched to the other side and cut off, and the power supply for applying a voltage to the RF low noise amplifier constituting the RF front end is cut off. Thus, the influence of unnecessary signals such as a jamming signal and a clutter signal is minimized.

Further, in the radar receiver according to the third invention, A
When the NL circuit is activated, the RF signal input from the antenna to the RF front end is controlled by the demultiplexing circuit to be branched to the other side and cut off, and the RF signal input to the RF front end is cut off by the RF switch, thereby jamming. The effect of unnecessary signals such as signals and clutter signals is minimized.

In the radar receiver according to a fourth aspect of the present invention, A
When the NL circuit is activated, the RF signal input from the antenna to the RF front end is controlled by the demultiplexing circuit to branch off to the other side and cut off, and the local signal to the mixer constituting the RF front end is cut off, thereby causing the jamming signal. -The influence of unnecessary signals such as clutter signals is minimized.

In the radar receiver according to a fifth aspect, A
When the NL circuit is activated, the RF signal input from the antenna to the RF front end is controlled by the demultiplexing circuit to be branched to the other side and cut off, and the power supply for applying a voltage to the RF low noise amplifier constituting the RF front end is cut off. At the same time, the local signal to the mixer constituting the RF front end is cut off, thereby minimizing the influence of unnecessary signals such as a jamming signal and a clutter signal.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a diagram showing a first embodiment of the present invention, in which 1 to 8 are the same as those shown in FIG. 9 is R from antenna
A demultiplexing circuit for cutting off the F signal without inputting it to the RF front end 2 and demultiplexing the signal to the other end, a terminator 10 for terminating the signal demultiplexed by the demultiplexing circuit 9, and an ANL circuit 7 for L An ANL operation signal notifying that the

Next, the operation will be described. ANL circuit 7
Operates, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 pass through the RF front end 2 and the IF amplifier 6 and are input to the ANL circuit 7, so that it is difficult to detect only normal reception noise. Since possible, incorrect gain setting was prevented, and accurate automatic noise level control was made possible. That is, the demultiplexing circuit 9 operates according to the ANL operation signal L from the ANL circuit 7 to cut off the input to the RF front end 2 and output the signal to the terminator 10. 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 is a view showing a second embodiment of the present invention, in which 1 to 8 are the same as those shown in FIG. Reference numeral 9 denotes a branching circuit for cutting off the RF signal from the antenna without being input to the RF front end 2 and branching the RF signal to the other side. Reference numeral 10 denotes a terminator for terminating the signal branched by the branching circuit 9; A switch L for turning on / off the power supply to the low noise amplifier 3 is an ANL operation signal indicating that the ANL circuit 7 is operating.

Next, the operation will be described. ANL circuit 7
Operates, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 pass through the RF front end 2 and the IF amplifier 6 and are input to the ANL circuit 7, so that it is difficult to detect only normal reception noise. Since possible, incorrect gain setting was prevented, and accurate automatic noise level control was made possible. That is, the demultiplexing circuit 9 operates according to the ANL operation signal L from the ANL circuit 7 to cut off the input to the RF front end 2 and output the signal to the terminator 10. At the same time, the switch S is turned off, and the voltage to the RF low noise amplifier 3 is cut off. 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 is a view showing a third embodiment of the present invention, in which 1 to 8 are the same as those shown in FIG. Reference numeral 9 denotes a branching circuit for cutting off the RF signal from the antenna without being input to the RF front end 2 and branching the RF signal to the other side. Reference numeral 10 denotes a terminator for terminating the signal branched by the branching circuit 9; A switch for turning on / off the input of the RF signal to the front end 2, L is ANL
An ANL activation signal indicating that the circuit 7 is operating.

Next, the operation will be described. ANL circuit 7
Operates, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 pass through the RF front end 2 and the IF amplifier 6 and are input to the ANL circuit 7, so that it is difficult to detect only normal reception noise. Since possible, incorrect gain setting was prevented, and accurate automatic noise level control was made possible. That is, the demultiplexing circuit 9 operates according to the ANL operation signal L from the ANL circuit 7 to cut off the input to the RF front end 2 and output the signal to the terminator 10. At the same time, the switch S is turned off, and the input of the RF signal to the RF front end 2 is cut off. Therefore, the unnecessary signal is greatly suppressed, and the ANL circuit 7 can detect only the noise generated by the receiving system.

Embodiment 4 FIG. 4 is a view showing a fourth embodiment of the present invention, in which 1 to 8 are the same as those shown in FIG. Reference numeral 9 denotes a branching circuit for cutting off the RF signal from the antenna without being input to the RF front end 2 and branching the RF signal to the other end. Reference numeral 10 denotes a terminator for terminating the signal branched by the branching circuit 9; A switch L for turning on / off the local signal to the switch 4 is an ANL operation signal indicating that the ANL circuit 7 is operating.

Next, the operation will be described. ANL circuit 7
Operates, unnecessary signals such as a jamming signal and a clutter signal received by the antenna 1 pass through the RF front end 2 and the IF amplifier 6 and are input to the ANL circuit 7, so that it is difficult to detect only normal reception noise. Since possible, incorrect gain setting was prevented, and accurate automatic noise level control was made possible. That is, the demultiplexing circuit 9 operates according to the ANL operation signal L from the ANL circuit 7 to cut off the input to the RF front end 2 and output the signal to the terminator 10. At the same time, the switch S is turned off, and the local signal from the local signal generator 5 to the mixer 4 is cut off.
Therefore, the unnecessary signal is greatly suppressed, and the ANL circuit 7
In, only the noise generated by the receiving system can be sensed.

Embodiment 5 FIG. 5 is a view showing a fifth embodiment of the present invention, in which 1 to 8 are the same as those shown in FIG. Reference numeral 9 denotes a branching circuit for cutting off the RF signal from the antenna without being input to the RF front end 2 and branching the RF signal to the other side. Reference numeral 10 denotes a terminator for terminating the signal branched by the branching circuit 9, and reference numeral S1 denotes RF. A switch for turning on / off the power supply to the low-noise amplifier 3, a switch for turning on / off a local signal to the mixer 4, and an LL operation signal for notifying that the ANL circuit 7 is operating.

Next, the operation will be described. ANL circuit 7
Operates, unnecessary signals such as jamming signals and clutter signals received by the antenna 1 pass through the RF front end 2 and the IF amplifier 6 and are input to the ANL circuit 7, so that it is difficult to detect only normal reception noise. Since possible, incorrect gain setting was prevented, and accurate automatic noise level control was made possible. That is, the demultiplexing circuit 9 operates according to the ANL operation signal L from the ANL circuit 7 to cut off the input to the RF front end 2 and output the signal to the terminator 10. At the same time, the switches S1 and S2 are turned off, and R
F The voltage to the low noise amplifier 3 is cut off, and the local signal from the local signal generator 5 to the mixer 4 is cut off. Therefore, the unnecessary signal is greatly suppressed, and the ANL circuit 7 can detect only the noise generated by the receiving system.

[0021]

According to the first to fifth embodiments of the present invention, unnecessary signals such as jamming signals when the ANL circuit operates can be ignored as compared with the conventional radar receiver. Because of this AN
There is an effect that the L circuit is properly operated to improve the setting accuracy of the reception system gain.

[Brief description of the drawings]

FIG. 1 is a diagram showing a radar receiver according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a radar receiver according to Embodiment 2 of the present invention.

FIG. 3 is a diagram showing a radar receiver according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a radar receiver according to a fourth embodiment of the present invention.

FIG. 5 is a diagram showing a radar receiver according to a fifth embodiment of the present invention.

FIG. 6 is a diagram showing a conventional radar receiver according to the present invention.

[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 branching circuit, 10 terminator, S switch, S1 switch, S
2 Switch, LANL activation signal.

Claims (5)

[Claims] 1. A radar receiver connected to a radar antenna for irradiating a target with a radio wave and receiving a reflected signal from the target, the RF (Rad) from the radar antenna.
io Frequency) signal and IF
(Intermediate Frequency) An RF front end that converts the signal into an signal, an IF amplifier that amplifies the output signal of the RF front end, and a receiver that is connected to the output side of the IF amplifier and that changes the reception gain and the signal noise level. An automatic noise level control circuit for preventing noise, 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 RF front end, R input from the antenna based on an operation signal issued from the noise level control circuit
A radar receiver comprising: a branching circuit for controlling transmission of an F signal to an RF front end; and a terminator for terminating a signal output from the branching circuit. 2. A radar receiver connected to a radar antenna for irradiating a target with radio waves and receiving a reflected signal from the target, amplifies the RF signal from the radar antenna and converts the RF signal into an IF signal. A front end,
An IF amplifier for amplifying an output signal of the RF front end; an automatic noise level control circuit connected to an output side of the IF amplifier for preventing a reception gain from changing and a signal noise level from changing; A power supply for applying a voltage to an RF low-noise amplifier constituting an end, a local signal generator for supplying a local signal to a mixer constituting the RF front-end, and the radar based on an operation signal issued from the automatic noise level control circuit A demultiplexing circuit for controlling transmission of an RF signal input from an antenna to an RF front end, a terminator for terminating a signal output from the demultiplexing circuit, and an RF low-frequency signal in the RF front end. A radar receiver comprising: a switch for turning on / off a power supply to a noise amplifier. 3. A radar receiver for irradiating a target with radio waves and receiving a reflected signal from the target, the RF receiver amplifying the RF signal from the radar antenna and converting the RF signal to an IF signal. A front end,
An IF amplifier for amplifying an output signal of the RF front end, an automatic noise level control circuit connected to the output side of the IF amplifier for preventing a reception gain from varying and a signal noise level from varying; A power supply for applying a voltage to an RF low-noise amplifier constituting an end, a local signal generator for supplying a local signal to a mixer constituting the RF front-end, and the radar based on an operation signal issued from the automatic noise level control circuit A branching circuit for controlling transmission of the RF signal input from the antenna to the RF front end, a terminator for terminating the signal output from the branching circuit, And an RF switch for turning on and off an RF signal to the RF front end. 4. A radar receiver connected to a radar antenna for irradiating a target with radio waves and receiving a reflected signal from the target, amplifies an RF signal from the radar antenna and converts the RF signal into an IF signal. A front end,
An IF amplifier for amplifying an output signal of the RF front end; an automatic noise level control circuit connected to an output side of the IF amplifier for preventing a reception gain from changing and a signal noise level from changing; A power supply for applying a voltage to an RF low-noise amplifier constituting an end, a local signal generator for supplying a local signal to a mixer constituting the RF front-end, and the radar based on an operation signal issued from the automatic noise level control circuit A demultiplexing circuit for controlling transmission of an RF signal input from an antenna to the RF front end, a terminator for terminating a signal output from the demultiplexing circuit;
A switch for turning on and off a local signal input to the F front end. 5. A radar receiver connected to a radar antenna for irradiating a target with radio waves and receiving a reflected signal from the target, amplifies an RF signal from the radar antenna and converts the RF signal into an IF signal. A front end,
An IF amplifier for amplifying an output signal of the RF front end; an automatic noise level control circuit connected to an output side of the IF amplifier for preventing a reception gain from changing and a signal noise level from changing; A power supply for applying a voltage to an RF low-noise amplifier constituting an end, a local signal generator for supplying a local signal to a mixer constituting the RF front-end, and the radar based on an operation signal issued from the automatic noise level control circuit A branching circuit for controlling transmission of an RF signal input from an antenna to a front end, a terminator for terminating a signal output from the branching circuit, and RF low noise in the RF front end A switch for turning on / off the power to the amplifier; and a on / off switch for a local signal input to the RF front end. Radar receiver characterized in that a switch for.