RU1840908C - Frequency tuning control device - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: device includes, between the output of a register and the second input of an inhibit circuit, series-connected unit decoder, second coincidence circuit, the second input of which is connected to the control input of a random number sensor, and a third divider circuit, the second input of which is connected to the second input of a first divider circuit.

EFFECT: high noise-immunity.

1 dwg

Description

The invention relates to the field of radar and can be used to control the restructuring of the carrier frequency of multi-frequency pulsed radio systems.

The most promising application of the control device in multi-frequency coherent-pulse radar stations with the adjustment of the carrier frequency from pulse to pulse.

Frequency tuning control devices for multi-frequency radio systems are known. For example, copyright certificate No. 1840895 by class. G01S 7/36, H04B 7/12 1977, ed. testimonial. No. 1840903 according to class G01S 1978

Frequency tunable pulse coherent radar exciter containing N local oscillators, the outputs of which are connected to the inputs of a power addition device, the output of which is connected to a transmitter mixer, the output of the probing signal former is connected to its second input, the outputs of the intermediate frequency generator and the trigger generator are connected to its two inputs a probe signal, a decoder of the local oscillator channel number, the N-outputs of which are connected to the control inputs of the corresponding local oscillators, and the input is connected to the outputs of the random number sensor and the interference analyzer, to the first control inputs of which the corresponding outputs of the control device are connected, the input of which is connected to the output of the probe trigger generator, the second output of the power splitter through the video detector is connected to the corresponding second control inputs of the random number sensor and the interference analyzer. In this exciter, it is possible to tune the frequency according to a random law and tune the radar to the frequency with the lowest noise level.

Its disadvantage is the inability to rebuild from interference during accidental adjustment. Frequency adjustment control device for autosw. No. 1840895, consisting of a decoder of the local oscillator channel number connected at the input to the output of the random number sensor, a video detector connected to the input of the interference analyzer and a control unit, the outputs of which are connected to the interference analyzer and the random number sensor, a separation circuit connected to the sensor at one input random numbers and the first prohibition circuit, but in another way - with an interference analyzer, video detector and a second prohibition circuit, the output of the separation circuit through the interference analyzer is connected to the comparison circuit and the first prohibition circuit, in The output of the comparison circuit is connected to the second input of the second inhibit circuit, the output of the comparison circuit is connected to the second input of the second inhibit circuit, and the last output is connected with a random number sensor, the output of the first inhibit circuit is connected to the decoder of the local oscillator channel number. Such a device makes it possible to rebuild from interference in the event of a random tuning of the radar carrier frequency.

The disadvantage of this device is that in order to search for a free channel in the presence of dense interference (several directors of narrow-band or targeted noise interference), in general, the number of samples of a random number greater than the number of channels is required.

Thus, during the search, a free channel may not be detected and the radar will probe at the last selected frequency, even if it is occupied by interference.

The closest in technical essence is the frequency tuning control device, consisting of an interference analyzer connected through one of the inputs to the output of the video detector and the input of the switch, and on the other, with the output of the first separation circuit, the input of which is connected to the second input of the switch, the input of the random number sensor and the inhibit circuit, the first output of the analyzer through the inhibit circuit is connected to one of the inputs of the second separation circuit and the second output is to the input of the comparison circuit, its output is connected to the third input of the switch, whose output is connected to the input of the register, and its output is connected to the input of the second comparison circuit, the output of which is connected to the control inputs of the matching circuit and the storage device, the outputs of the random number generator are connected to the information inputs of the memory, and the outputs of the memory are connected to the second inputs of the second comparison circuit and coincidence circuit, the output of the coincidence circuit is connected to the second input of the second separation circuit, the outputs of the control device are connected to the inputs of the interference analyzer, random number sensor and the second separation circuit, its output connected to the 4th input of the switch.

The disadvantage of this device is that in a rapidly changing interference environment, the operator cannot quickly track the change in the type of interference by switching the tuning modes. For example, if the radar operates with random tuning and obstruction is set, then the sounding will occur all the time on channels occupied by interference, and it takes time for the operator to detect the inefficiency of this mode.

The aim of the invention is to increase the noise immunity of the radar and simplify the work of the radar operator in a rapidly changing jamming environment.

This goal is achieved in that in a device containing an interference analyzer, a video detector, a switch, a register, two comparison schemes, a random number sensor, a storage device, two separation schemes, a prohibition circuit and a control unit, the input interference analyzer being connected to the output of the video detector, the input of the switch, the second input of the analyzer is connected to the output of the separation circuit, the input of the separation circuit is connected to the input of the switch and the random number sensor, the first output of the analyzer is connected through the ban circuit to the second input separation circuit, the second output of the analyzer is connected to the first comparison circuit, the output of which is connected in series with the register and the input of the second comparison circuit, the output of which is connected to the control inputs of the storage device and the matching circuit, the inputs of the storage device are connected to the outputs of the random number sensor, and its output - with the information inputs of the second comparison circuit and the matching circuit, the output of the matching circuit is the second input of the second separation circuit, the output of which is connected to the fourth input m of the switch, the outputs of the control unit are connected to the inputs of the interference analyzer, random number sensor and separation circuit, a unit decoder, a second matching circuit and a third separation circuit are introduced, the decoder inputs connected to the register outputs, the decoder output to the input of the second matching circuit, and its the second input is connected to the input of the random number sensor, the output of the matching circuit through the third separation circuit is connected to the second input of the inhibit circuit, the second input of the third separation circuit is connected to the input of the first circuit section tions that can automatically, without human intervention, switch from restructuring at random in the operation mode setting on the frequency with minimum interference if all the frequencies occupied by an obstacle, and in all places the unit register recorded.

The drawing shows a functional diagram of the device, which consists of a switch 1, a control unit 2, a random number sensor 3, an interference analyzer 4, a register 5, a video detector 6, a separation circuit 7, a prohibition circuit 8, a comparison circuit 9, a comparison circuit 10, II, a storage device 11, a matching circuit 12, a separation circuit 13, a decoder 14, a matching circuit 15, a separation circuit 16.

The separation circuit 7 is connected at the input to the third input of the switch 1, the random number sensor 3 and the coincidence circuit 15, and at the output to the interference analyzer 4. The video detector is connected to the input of the analyzer 4 and the second input of the switch 1. The control node 2 is connected to the analyzer 4, the sensor 3 and the separation circuit 13. The analyzer 4 at the outputs is connected to the inputs of the ban circuit 8 and the comparison circuit 9. The output of the comparison circuit 9 is connected to the first input of the switch 1, with the other inputs of which the outputs of the separation circuit 13 are connected, the same outputs are fed to the local oscillators. The outputs of the switch 1 are connected to the register 5, and its outputs with the comparison circuit 10 and the decoder 14, the decoder output with the second input of the matching circuit 15, and its output with one of the input of the separation circuit 16, the second input of which is connected to the second input of the separation circuit 7, the output of the separation circuit 16 with the second input of the prohibition circuit 8. The random number sensor 3 is connected to the input of the storage device 11, and its outputs are connected to the inputs of the comparison circuit 10 and the matching circuit 12, the output of the comparison circuit 10 is connected to the second input of the matching circuit 12 and the input of the storage device 11, and the output of the matching circuit 12 is connected to the third the input of the separation circuit 13.

The device operates as follows. When a command to turn on the adjustment according to a random law in the interval of the working range of the radar is received, random numbers from the DSCH 3 are recorded in the memory 11, recording in the memory occurs until all N different numbers are recorded in the memory. During the return path of the indicator beam, an interference analyzer 4 operates, the input of which receives an interference signal, a channel is searched with a minimum interference level, as in the automatic tuning mode for a channel with the lowest interference level. At the same time, the signal from the second output of the interference analyzer 4 is compared in the first comparison circuit 9 with a threshold only in the random tuning mode. If the threshold is exceeded and if there is a resolution potential from the video detector 6, the switch 1 allows the unit to be written to that category of the WP 5 register, which corresponds to the number of the included local oscillator. Thus, after the analysis is completed, in the discharges of WP 5 corresponding to the channel numbers, the interference level of which has exceeded the threshold, one will be recorded, and the channel number code with the minimum interference level is stored in analyzer 4. If there is narrow-band or creeping interference, the units are not recorded in all bits of register 5, then the matching circuit 15, through the separation circuit 16, gives a ban signal to the input of the ban circuit 8 and the channel number code with the lowest interference level from the analyzer 4 does not go to the input of the separation circuit 13 .

In the presence of obstruction during operation of the radar in random tuning mode, the noise level in all frequency channels will exceed the threshold and units will be recorded in all bits of register 5. The decoder 14 issues a permit to the inhibit circuit 8 through the coincidence circuit 15 and the separation circuit 16 and the code of the working channel number with the lowest interference level recorded in the analyzer register 4, will go through the open circuit 8 of the ban on the inputs of the separation circuit 13 and then on to turn on the selected local oscillator. Since units in all digits are recorded in the register 5, the comparison circuit 10 will constantly output a prohibition signal to the coincidence circuit 12, and the storage device 11 will not be connected to the separation circuit 13.

Thus, the radar switches to adaptive tuning mode and will probe at the operating frequency with the least interference level.

The use of this device makes it possible to increase the detection range of useful signals in a rapidly changing interference environment.

.An approximate calculation of the effectiveness of the described operation algorithm can be done based on the following premises. Suppose that when the random tuning mode was turned on, the interference changed from sighting to obstructive with the spectral power density averaged over all radar frequencies equal to $$K_{\mathrm{from}R}=\frac{P_{P\mathrm{about}mex\mathrm{and}\text{wed}}}{P_{\mathrm{from}\mathrm{about}b\mathrm{from}t\mathrm{at}.\text{noise}}}$$

.

In the prototype, in this case, the selected one will be one of the frequencies occupied by the noise, the number of which turned out to be the last in the sequence of random numbers recorded in the storage device. The result accumulating burst resulting signal / noise ratio deteriorates in K _cf. times.

.In the proposed device, in this case, the sounding will occur at a frequency with a minimum level of interference. From the literature [1, 2] it is known that this level exceeds the level of intrinsic noise by K _min times, which is less than K _cf. Then the increase in the detection range when using the proposed device will be $$\frac{D_{\mathrm{one}}}{{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="00000006.png"\; state="\{\{state\}\}">D</figure-callout>}}_2}=\sqrt[\mathrm{four}]{\frac{K_{\mathrm{from}R}}{K_{\min }}}$$

.

Typical values are:

K _cf = 20 dB (÷ 100 times)

$$K_{\mathrm{from}R}=\frac{P_{P\mathrm{about}mex\mathrm{and}\text{wed}}}{P_{\mathrm{from}\mathrm{about}b\mathrm{from}t\mathrm{at}.\text{noise}}}$$

K _min = 15 dB (÷ 30 times) $$K_{\min }=\frac{P_{P\mathrm{about}mex\mathrm{and}\text{min}}}{P_{\mathrm{from}\mathrm{about}b\mathrm{from}t\mathrm{at}.\text{noise}}}$$

.

.Then $$\frac{D_{\mathrm{one}}}{{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="00000006.png"\; state="\{\{state\}\}">D</figure-callout>}}_2}=\sqrt[\mathrm{four}]{\frac{\mathrm{one\; hundred}}{\mathrm{thirty}}}=1.34$$

.

Thus, the use of the invention may in some cases, namely in a rapidly changing interfering environment, provide an increase in range by 30%.

LITERATURE

1. Bezmaga V.M. V.R.E., issue 6 (36), Determination of the statistical characteristics of active interference according to the results of summer tests, 1969

2. Levit Ya.I. V.S.R.E., issue 15, On the effect of fluctuations in the intensity of active noise interference on the radar direction-finding characteristics, 1973

Claims (1)

Frequency adjustment control device according to copyright certificate No. 1840903, characterized in that, in order to increase noise immunity, series-connected “units” decoder connected between the register output and the second input of the inhibit circuit are inserted, the second matching circuit, the second input of which is connected to the control input a random number sensor, and a third separation circuit, the second input of which is connected to the second input of the first separation circuit.

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