JPH056381U - Tracking receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a device in which the power spectrum of a pulse of a range gate becomes an unnecessary signal and does not cause a problem that the signal-to-noise ratio of a tracking receiver is deteriorated. [Structure] A range gate function is not provided in the IF section, but a gate circuit for preventing transmission leakage is used, and a range gate function is provided in the RF section.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tracking receiver used for a pulse radar.

[0002]

[Prior Art]

 FIG. 4 is a block diagram showing a part of the configuration of a conventional tracking receiver of this type. In the figure, 1 is an active phased array antenna, 2 is a voltage controlled variable attenuator, 3 is a low noise RF amplifier, 4 is a mixer, 5 is an IF amplifier, 6 is a gate circuit, 7 is a detection circuit, and 8 is a gate generator. is there.

In the configuration as shown in FIG. 4, a part of the transmission signal from the active phased array antenna 1 is input to the voltage control type variable attenuator 2 as leakage, and then the reception signal from the target is slightly delayed with time. Is input to the voltage controlled variable attenuator 2. This voltage-controlled variable attenuator 2 has the maximum attenuation during the time when a part of the transmission signal is input, and the time when the reception signal from the target passes depends on the magnitude of the reception signal from the target. It is the amount of attenuation. Therefore, part of the transmission signal is not input to the low noise RF amplifier 3, but only the reception signal from the target is input.

This operation is generally called transmission blanking, and the control signal applied to the voltage-controlled variable attenuator 2 is called a blanking gate Vb here. FIG. 2 shows the timing of this transmission blanking, and as shown in the figure, the blanking gate Vb is applied to the voltage-controlled variable attenuator 2 only during the time of transmission.

The received signal from the target is amplified by the low noise RF amplifier 3 and converted into an IF signal by the mixer 4. The IF amplifier 5 amplifies this IF signal and inputs it to the gate circuit 6. The range gate Vr is applied to the gate circuit 6 by the gate generator 8 and the IF signal, that is, the received signal from the target is passed only during the time when the range gate Vr is applied. FIG. 2 shows this timing diagram. The role of the range gate Vr is to reduce extra noise and unnecessary signals by operating the receiver only during the time when the target exists. This function is usually always included in the receiver for tracking radar.

The IF signal that has passed through the gate circuit is converted into a video signal by the detection circuit 7, and then sent to the signal processing unit.

[0007]

[Problems to be solved by the device]

 However, there are problems with this type of conventional tracking receiver. Since the range gate Vr has a pulse waveform as shown in FIG. 2, when the frequency is plotted on the horizontal axis, its power spectrum spreads to several hundred MHz as shown in FIG. Therefore, this power spectrum will include the IF frequency, and as a result, the tracking receiver will generate an unnecessary signal. This becomes a very important defect that the signal-to-noise ratio deteriorates especially for an H-PRF radar device that performs signal processing on the frequency axis.

[0008]

[Means for Solving the Problems]

 The present invention has been made to solve the above-mentioned problems, and it is intended to configure a gate circuit having a range gate function at a frequency where its power spectrum does not exist. That is, since the power spectrum component of the range gate is several hundreds MHz or more, it may be installed in the RF portion before the mixer 4 in the configuration example of FIG.

[0009]

[Action]

 If a gate circuit for the range gate is installed in the RF part, the power spectrum component of the range gate is out of the signal pass band of the RF part, so that it cannot be detected as a video output. Further, in the present invention, since the gate function of the range gate is provided in parallel with the blanking gate function in the voltage control type variable attenuator 2 in the configuration example of FIG. 4, it is also very advantageous in simplifying the hardware of the tracking receiver. Becomes

[0010]

【Example】

 FIG. 1 is a block diagram showing a part of a tracking receiver showing an embodiment of the present invention. In the figure, 1 to 7 are exactly the same as the above conventional device, and 9 is a gate generator.

Next, the operation will be described. In FIG. 1, a range gate Vr is added to the voltage controlled variable attenuator 2. Therefore, only the reflected signal from the target input from the active phased array antenna 1 is sent to the low noise RF amplifier 3. Conversely, this means that the leak of the transmission signal input from the active phased array antenna 1 is not passed, and at the same time, it also serves as a blanking gate.

The reflected signal from the target amplified by the low noise RF amplifier 3 passes through the mixer 4, the IF amplifier 5 and the detection circuit 7 and is sent to the signal processing unit. Since the function is provided, no gate circuit is provided in the IF section. Therefore, generation of unnecessary signals that pass through the IF section is eliminated.

Although the voltage-controlled variable attenuator 2 generates an unnecessary signal due to the power spectrum of the range gate VR, it does not pass the low-noise RF amplifier 3 in the next stage and the unnecessary signal. As a result, unnecessary signals are gone.

[0014]

[Effect of the device]

 As described in detail above, by using the present invention, it is possible to solve the problem that an unnecessary signal is generated and to obtain a very beneficial effect that the hardware of the tracking receiver can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing a part of a configuration of a tracking receiver according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the operation of this invention.

FIG. 3 is a waveform diagram for explaining the operation of this invention.

FIG. 4 is a diagram showing a conventional tracking receiver.

[Explanation of symbols]

 1 Active Phased Array Antenna 2 Voltage Controlled Variable Attenuator 3 Low Noise RF Amplifier 4 Mixer 5 IF Amplifier 6 Gate Circuit 7 Detection Circuit 8 Gate Generator 9 Gate Generator

Claims (1)

[Claims for utility model registration] Claims: 1. An active phased array antenna for receiving and amplifying a received signal from a target, and an output signal of the active phased array antenna are passed therethrough to prevent transmission signal leakage. A voltage-controlled variable attenuator with a range gate function for attenuating unnecessary signals, a low-noise RF amplifier that amplifies the output signal of this voltage-controlled variable attenuator, and an output signal of this low-noise RF amplifier to an IF signal. A mixer for converting and an IF for amplifying the mixer output signal
Tracking reception comprising an amplifier, a detection circuit for converting an output signal of the IF amplifier into a video signal and sending the video signal to a signal processing unit, and a gate generator for controlling the voltage control type variable attenuator. Machine.