JPH054068U - Receiver for radar - Google Patents

Abstract

(57) [Abstract] [Purpose] The purpose of this invention is to effectively block unwanted signals from the antenna when the automatic noise level control circuit is operating, and to improve the accuracy of the gain setting of the receiving system. [Structure] Amplifies the signal received from the antenna and
RF (Radio Frequency) for converting to (Intermediate Frequency) signal
A front end, an amplifier for amplifying an output signal of the RF front end, an automatic noise level control circuit which is installed after the amplifier to prevent the reception system gain from varying and the signal noise level to vary, and the RF front. It is composed of a switch for turning on / off an RF signal and a local signal to the end.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a radar receiver that effectively blocks an unnecessary signal input from an antenna when an automatic noise level control circuit (Automatic Noise Leveling, hereinafter referred to as an ANL circuit) is activated.

[0002]

[Prior Art]

 As a conventional device of this type, there is one shown in FIG. In the figure, 1 is an antenna, 2 is an RF front end that amplifies the signal from 1 and converts it into an IF signal, 3 is an amplifier that amplifies the signal from this RF front end 2, and 4 is a gain of the receiving system. Is an ANL circuit that keeps the signal constant to prevent fluctuations in the signal noise level.

Next, the operation will be described. The received signal from the antenna 1 is amplified and IF-converted by the RF front end 2, and then amplified again by the IF amplifier 3 connected thereto. The ANL circuit 4 connected after the IF amplifier 3 can prevent the reception system gain from fluctuating and the signal noise level to fluctuate because the performance of electric parts and the like changes with temperature.

[0004]

[Problems to be solved by the device]

 The conventional radar receiver as described above has the following problems. In other words, the AGC / STC voltage is kept at 0V during the ANL noise detection time so that the ANL noise does not change due to the AGC / STC voltage. Therefore, if a strong jamming occurs during 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 to change the tracking sensitivity or the tracking error due to the change of the signal level, and the STC voltage is applied to prevent the receiver from being saturated in the search mode.

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

[0006]

[Means for Solving the Problems]

 In the radar receiver according to the present invention, the effects of unnecessary signals such as jamming signals and clutter signals are minimized by blocking the RF signal and the local signal to the RF front end when the ANL circuit is activated. It was done.

[0007]

[Action]

 The radar receiver according to the present invention cuts off the RF signal and the local signal to the RF front end when the ANL circuit is activated, so that unnecessary signals such as jamming signals and clutter signals input to the receiving system are suppressed and reception is performed. The accuracy of system gain setting 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 is an antenna, 2 is an RF front end, 3 is an amplifier, 4 is an ANL circuit, 5 is a switch, 6 is a control signal line, and 7 is a local signal generator.

The operation of the present invention will be described. When the ANL circuit 4 operates, unwanted signals such as jamming signals and clutter signals received by the antenna 1 pass through the RF front end 2 and the amplifier 3 and are input to the ANL circuit 4 to detect only normal reception noise. Since it is impossible to set the gain, it is possible to prevent an incorrect gain setting and to enable accurate automatic noise level control. In other words, when the ANL circuit 4 is activated, the control signal from 4 turns off the switch 5 via the control signal line 6 to cut off the RF signal and the local signal to the RF front end, thereby eliminating the above-mentioned unnecessary from the antenna 1. The signal is largely suppressed, and the ANL circuit 4 can detect only the noise generated by the receiving system.

[0010]

[Effect of the device]

 As described above, according to the present invention, the RF signal and the local signal to the RF front end are cut off when the ANL circuit is activated, so that the jamming signal when the ANL circuit is activated is compared to the conventional radar receiver. Unnecessary 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 Switch 6 Control Signal Line 7 Local Signal Generator

Claims (1)

[Claims for utility model registration] Claim 1. Amplification of a signal received from an antenna and IF (Intermediate Frequency)
y) RF (Radio Frequency) for converting into a signal
cy) a front end, an amplifier for amplifying an output signal of the RF front end, an automatic noise level control circuit which is installed after the amplifier and prevents the reception system gain from varying and the signal noise level to vary. A radar receiver comprising a local signal generator for supplying a local signal to a mixer in the RF front end, and a switch for turning on / off the RF signal and the local signal to the RF front end.