JPH07248372A - Receiver for radar - Google Patents

Abstract

PURPOSE:To reduce influence such as a jamming signal or a clutter signal by cutting off electric power supply of a low noise amplifier, a local signal and an RF signal on an RF front end when an automatic noise level control circuit is actuated. CONSTITUTION:An RF switch 9 is cut off by an ANL actuating signal 10 from an automatic noise level control (ANL) circuit 4, and thereby, voltage impression on an RF low noise amplifier 6 in an RF front end 2, a local signal and an FR signal to a mixer in the front end 2 are cut off. Thereby, an unnecessary signal such as a jamming signal or a clutter signal received by an antenna 1 is restrained, and the circuit 4 comes to sense only a noise generated by a receiving system, so that gain setting accuracy of the receiving system is improved.

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 Leveli).
ng, hereinafter referred to as an ANL circuit), the present invention relates to a radar receiver configured to effectively block an unnecessary signal input from an antenna.

[0002]

2. Description of the Related Art A conventional device of this type is shown in FIG. In the figure, 1 is an antenna, 2 is a signal from the antenna 1 and IF (Intermedia)
The RF front end 3 for converting into a teFrequency signal is the RF front end (Fronten).
d) An IF amplifier that amplifies the signal from 2 and an ANL (Automatic Noise Level) 4 that keeps the gain of the receiving system constant and prevents signal noise level fluctuations.
(ring) circuit, 5 is a local signal generator that supplies a local signal to the RF front end 2.

Next, the operation will be described. The reception signal received by the antenna 1 is amplified and IF signal converted by the RF front end 2 and is connected to the output side of I.
It is amplified again by the F amplifier 3. The ANL circuit 4 connected to the output side of the IF amplifier 3 can prevent the performance of electric components and the like from changing due to temperature, so that the gain of the receiving system and the level of signal noise can be prevented from changing.

[0004]

The radar receiver as described above has the following problems. That is, A
Set the AGC / STC voltage to 0 during the ANL noise detection time so that the NL noise does not fluctuate due to the AGC / STC voltage.
I keep it at V. Therefore, when a strong jamming is received at the time of this detection, the ANL circuit cannot detect only the normal reception noise, resulting in an incorrect reception system gain setting. The AGC voltage is applied in order to prevent the saturation of the receiver in the search mode, for example, in order to reduce the tracking sensitivity variation or the tracking error due to the signal level variation.

The present invention has been made in order to solve the above problems, and provides a receiver for radar that effectively blocks unnecessary signals received by an antenna when the ANL circuit is operating.

[0006]

SUMMARY OF THE INVENTION In a radar receiver according to the present invention, an ANL circuit operation is performed for a power source for applying a voltage to a low noise amplifier constituting an RF front end and a local signal and an RF signal to the RF front end. By occasionally blocking, the influence of unwanted signals such as jamming signals and clutter signals is minimized.

[0007]

The radar receiver according to the present invention cuts off the local signal and the RF signal to the power supply for applying the voltage to the low noise amplifier constituting the RF front end and the RF front end during the operation of the ANL circuit. Unwanted signals such as jamming signals and clutter signals that are input to are suppressed, and the accuracy of the gain setting of the receiving system is improved.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 to 7 are shown in FIG. 8
Is a power supply for applying a voltage to the RF low noise amplifier 6 forming the front end 2, 9 is a signal received by the antenna 1, the voltage applied to the RF low noise amplifier 6 and the mixer 7 forming the front end 2 An RF switch 10 for turning on / off a local signal to notify the RF switch 9 that the ANL circuit 4 is operating.
It is an operation signal.

The operation of the present invention will be described. ANL
When the circuit 4 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 3 and are input to the ANL circuit 4.
Since it is impossible to detect only the regular reception noise, it is possible to prevent the gain setting from being incorrect and to enable accurate automatic noise level control. That is, the ANL operation signal 10 from the ANL circuit 4 turns off the RF switch 9,
As a result, the voltage application to the RF low noise amplifier 6 forming the RF front end 2 and the local signal and the RF signal to the mixer 7 forming the RF front end 2 are cut off. Therefore, the unnecessary signal from the antenna 1 is significantly suppressed, and the ANL circuit 4 can detect only the noise generated by the receiving system.

[0010]

As described above, according to the present invention, the RF
When the ANL circuit is in operation, the power supply for applying voltage to the RF low-noise amplifier that constitutes the front end and the local signal and RF signal to the RF front end are shut off during operation of the ANL circuit. Unwanted signals such as jamming signals can be ignored. Therefore, there is an effect that the ANL circuit is properly operated and the setting accuracy of the reception system gain is improved.

[Brief description of drawings]

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

FIG. 2 is a block diagram of a conventional radar receiver.

[Explanation of symbols]

 1 Antenna 2 RF Front End 3 Amplifier 4 ANL Circuit 5 Local Signal Generator 6 RF Low Noise Amplifier 7 Mixer 8 Power Supply 9 RF Switch 10 ANL Operation Signal

Claims (1)

[Claims] 1. Amplifying a received signal received by an antenna,
And IF (Intermediate Frequency)
cy) RF (Radio Frequency)
ncy) a front end, an RF low noise amplifier for amplifying an output signal of the RF front end, and an automatic noise level which is connected to the output side of the amplifier and prevents the gain of reception from varying and the noise level of the signal to vary. A control circuit, a power supply that applies a voltage to an IF amplifier that constitutes the RF front end, a local signal generator that gives a local signal to a mixer that constitutes the RF front end, a local signal to the RF front end, and an RF signal. A radar receiver comprising a signal and an RF switch for turning on and off the power source.