RU1840985C - Signal discriminator - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: signal discriminator comprises a frequency converter, a delay line, three circulators, two convolvers, two threshold detectors and a logic circuit, connected to each other in a certain manner.

EFFECT: broader functional capabilities.

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Description

The invention relates to pulse information receivers operating in a wide range of signal parameters, and is intended for use in electronic intelligence systems and passive target designation systems.

Currently known signal discriminators implemented on the basis of devices for convolution of signals on surface acoustic waves (convolvers).

As the first analogue, we consider the device described in the report on the Parsek Research Institute of the Quantum Research Institute, which distinguishes between pulsed signals with a constant filling frequency (simple signals) and signals with linear frequency modulation (LFM).

The known device has a high sensitivity achieved due to the temporary compression of the chirp signals. The disadvantage of this device is the inability to distinguish between signals with binary phase shift keying (FM).

As a second analogue, we consider the device according to ed. testimonial. No. 1840894, application for invention 2202015 with a priority of 04/05/1976, in which a distinction is made between LFM, FM, and simple signals.

The known device has a high sensitivity and high reliability of distinguishing signals. A disadvantage of the known device is a narrow range of variation of the parameters of the modulating functions when distinguishing simple signals.

As a third analogue, we consider the device according to ed. testimonial. No. 1840905 (application for invention 2231687 dated 12/12/1977), which distinguishes LFM, FM, and simple signals in a fairly wide range of parameters of their modulating functions. A common disadvantage of this and the considered devices is limited functionality, i.e. known devices distinguish only two or three types of signals.

An analysis of the probing signals of shipborne radars of a likely enemy showed that modern and promising radar systems are characterized by a variety of probing signals, the choice of which is determined by the nature of the problem being solved and the characteristics of the radar situation. Along with the widespread LFM (unidirectional), FM, and simple signals, signals with symmetric frequency modulation (V-shaped FM) are used in practice, which make it possible to obtain uncorrelated errors in measuring range and speed, and to efficiently distinguish moving targets against the background of passive interference.

By technical nature, the closest to the proposed device is a device by ed. testimonial. No. 1840905 from 12/12/1977, which is chosen as a prototype.

The known device contains a block for generating a reversed signal, a block for generating a difference signal, a delay line, two adders (circulators), a frequency converter, a convolver, a threshold detector, and a logic circuit. The input of the device is connected to the inputs of the inverse signal generating unit, the delay line, the differential signal generating unit and to the second inputs of the circulators. The output of the inverse signal generating unit is connected to the first input of the first circulator, the output of which is connected to the first input of the convolver. The output of the delay line is connected to the first input of the second circulator, the output of which through the frequency converter is connected to the second input of the convolver. The second input of the differential signal generating unit and the threshold detector input are connected to the output of the convolver. The outputs of the differential signal generating unit and the threshold detector are connected to the inputs of the logic circuit.

A disadvantage of the known device is the inability to distinguish between signals with a V-shaped FM, i.e. The known device has limited functionality.

The aim of the invention is the expansion of functionality.

This goal is achieved by the fact that in a known device containing a unit for generating an inverse signal, a frequency converter, a delay line, two circulators, a convolver, a threshold detector, a logic circuit, the input of the device is connected to the input of the unit for generating an inverse signal, with a second input of the first circulator and with the input of the delay line, the output of the inverse signal generating unit is connected to the first input of the first circulator, the output of which is connected to the first input of the convolver, the output of the delay line with connected to the first input of the second circulator, the output of the convolver through a threshold detector is connected to the first input of the logic circuit, the third circulator is introduced, the second convolver and the threshold detector, the input of the device through the frequency converter connected to the second input of the second circulator, the output of which is connected to the second input of the first convolver, the first and second inputs of the third circulator are respectively connected to the input and output of the delay line, and the outputs of the first and third circulators are connected to the inputs of W the second convolver, the output of which through the second threshold detector is connected to the second input of the logic circuit.

The introduction of such elements and connections into the known device made it possible to obtain a new effect — an extension of functionality expressed in distinguishing, along with LFM, FM, and simple signals from V-shaped FM signals.

Figure 1 presents a block diagram of the proposed device.

The device comprises a frequency converter 1, a delay line 2, an inverse signal generation unit 3, circulators 4, 5, 6, a logic circuit 7, threshold detectors 8, 11, convolvers 9, 10.

The inputs of the inverse signal generating unit 3, the frequency converter 1, the delay line 2 and the second inputs of the circulators 4, 6 are connected together and are the input of the device.

The output of the inverse signal generating unit 3 is connected to the first input of the circulator 4, the output of which is connected to the first input of the convolver 9 and to the second input of the convolver 10. The inputs of the circulator 5 are connected to the outputs of the delay line 2 and the frequency converter 1, in addition, the output of the delay line 2 is connected to the first input of the circulator 6. The outputs of the circulators 5, 6 are respectively connected to the second input of the convolver 9 and the first input of the convolver 10. The outputs of the convolvers 9, 10 through threshold detectors 8, 11 are respectively connected to the inputs of the log eskoy circuit 7.

Consider the operation of the proposed device.

In the discriminator, signal processing is divided into two stages. At the first stage, the signals processed at the inputs of the convolvers 9, 10 directly and through the frequency converter 1 are processed. In this case, the frequency conversion is carried out in such a way that there are interchanged LFM signals at the inputs of the convolver 9. At the second stage of processing, convolvers 9, 10 carry out the convolution of the signals addressed in block 3 and delayed in block 2.

A distinctive feature of signal processing with a V-shaped FM at the first stage is that two compressed pulses are generated at the output of the threshold detector 8. The detection of pulses is performed by threshold detectors 8, 11, which output standard-amplitude video pulses to logic 7. The number of video pulses formed at the outputs of the threshold detectors 8, 11 at the I and II stages of processing the LFM, FM, V-shaped FM and simple signals are shown in table No. 1.

Table 1 Signal type 1st stage of processing 2nd stage of processing Total number of pulses Threshold Detector 8 Threshold Detector 11 Threshold Detector 8 Threshold Detector 11 Plain one one one one four Chrome one 0 one one 3 Fm 0 0 one one 2 V-arr. World Cup eleven one one one 5

Analysis of the data in table No. 1 shows that in the total number of pulses arriving at logic 7, information about the type of modulation of the incoming signal is enclosed. When 7 pulses are received at the inputs of the logic circuit, a decision is made to receive the FM signal, when 3 pulses are detected, the LFM signal is received, when 4 pulses are received, a simple signal is received, and when 5 pulses are detected, a V-shaped FM.

All elements of the proposed device are made according to known standard schemes.

Thus, the proposed device allows you to get a new effect - the expansion of functionality, expressed in the distinction between signals with a V-shaped FM. This allows to improve the quality of solving the problems of selection and identification of signals in radio intelligence systems and passive target designation systems, increase the likelihood of correct identification of the type of radar and its carrier, and also increase the effectiveness of electronic suppression of the radar of a likely enemy by radio countermeasures systems.

Claims (1)

A signal discriminator comprising a frequency converter, a delay line connected in series with a first circulator, and a reversed signal shaper connected in series, a second convolver circulator, a threshold detector and a logic circuit, while the input of the device is connected to the inputs of the reversed signal shaper, delay line and second inputs of the first and the second circulators, characterized in that, in order to ensure the possibility of distinguishing between signals with a V-shaped frequency modulation, a third a circulator and, in series, a second convolver and a second threshold detector, wherein the first input of the third circulator is connected to the input of the device through the frequency converter, the output is connected to the second input of the first convolver, and the second input is connected to the second input of the first circulator, which is connected to the first input of the second convolver, the second input of which is connected to the output of the second circulator, the output of the second threshold detector is connected to the second input of the logic circuit.

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