SU978377A1 - Device for detecting noise-like signals - Google Patents

Description

(54) DEVICE FOR SEARCH OF NON-LIKE SIGNALS

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The invention relates to devices for detecting, recognizing and receiving complex noise-like signals (PSS) and can be used to search for complex noise-like signals in radar, telemetry and communication systems.

Known search device noise. These signals contain a serially connected mixer, a wideband amplifier, a demodulator, a narrowband amplifier, a low-pass filter (LPF) detector and a controlled local oscillator whose output is connected to the first input of the mixer, the second input of which is a device input, and the first the OR element, the output of which is connected to the second input of the demodulator and through a serially connected discriminator, correction amplifier, controlled clock generator, the first valve and the second element OR to, the input generator psevdosluchay2

signals (pop), whose outputs are connected to the first inputs of switch valves and reference inputs, channel correlators, the signal inputs of which, as well as the second input of the discriminator are connected to the output of the wideband amplifier, and the first inputs of the unit scan, connected to the output of the first key, to

The 10th input of which is connected via the time interval former, the output of the additional threshold unit, whose input is combined with the first input of the main threshold unit, the output of which is connected to the second input of the first key, and the outputs of the channel correlators through the switch valves OR , while the output of the controlled clock generator through the delay element is connected to the first input of the second valve and is not immediately scanned to the second input of the block, the first output of which is Connected to the second input of the controlled local oscillator, and the second and third outputs of the scanning unit are connected respectively to the second input of the first valve and through the second valve to the second input of the second element OR U The well-known device has a long search time for non-stationary and dependent interferences - reduction of search time. To achieve this goal, a noise-like search device containing serially connected - a mixer, a broadband amplifier, demodulator, narrowband amplifier, a low-pass filter (LPF) detector and a controlled local oscillator, the output of which is connected to the first input of the mixer, the second the input of which is the input of the device, as well as the first OR element, the output of which is connected to the second input of the demodulator and Lepe3 serially connected discriminator, correction amplifier, controlled by the beat generator, the first valve and the second element OR — to the input of a pseudo-random signal generator (PSP), whose outputs are connected to the first inputs of commutator valves and the reference inputs of channel correlators, to the signal inputs of the KOTopblx, as well as the output of the wideband amplifier , and the output of the first key is connected to the fault inputs of the channel correlators and the first input of the scanning unit; the output of the additional threshold is connected to the first input of which through the time interval generator th block, the input of which is combined with the first threshold WMOs house main unit, whose output is connected to the second row WMOs first key, and outputs the channel correlators through valves .Connect commutator to the inputs of the first OR gate, wherein the control "emogo output. The clock generator is connected via the delay element to the first input of the second valve and directly to the second input of the scanning unit, the first output of which is connected to the second input of the controlled local oscillator, and the second and third outputs of the scanning unit are connected respectively to the second input of the first valve and through the second valve to the second input of the second element OR, a block for selecting the maximum signal, a frequency divider, a second key and a third key connected in series, a shift register, an additional input the time intervals and the controllable key, as well as the first additional delay element, the coincidence unit and the serially connected decoder, the second additional delay element and the pulse counter, the direct output of which is connected to the control inputs of the second and third keys, and the output of the controlled clock generator through a frequency divider connected to the information input of the second key and the second input of the pulse counter, the inverse output of which is connected to the second input of the controlled key, the control input for the additional threshold block and the first input of the match block, to the second, third and fourth inputs of which the output of the decoder, the first output of the shift register and the input of the first additional delay element are connected, and the output of the match block is connected to the first input of the scanning unit, the input of the first additional delay element and the second input of the shift register, the second output of which is connected to the input of the decoder, while the output of the second key is connected to the first input of the scanning unit, quarters the output of which is connected to the third inlet of the controlled key, the output of which is connected to the second input of the main threshold unit, the output of the additional threshold unit is connected to the information input of the third key, and the outputs of the channel correlators are connected to the combined the inputs of the main and additional threshold units The drawing shows a structural electrical circuit of the device. The device for searching noise-like signals contains a mixer 1, a broadband amplifier 2, a demodulator 3, a narrow-band amplifier, a detector 5 with a low-pass filter (low pass filter), a controlled oscillator 6, a discrimination-. torus 7 correction amplifier 8, controlled clock generator 9 per5978377

the first valve 10, the first element OR 11, the first search cycle is set to delay element 12, the second valve state of the counter 2b im13, the generator 1 pseudo-random sequence (PSP), switch valves 15, the second element OR 1b, 5 pours on

channel correlators 17, main threshold unit 18, additional threshold unit 19, time generator 20, first key 21, scan unit 22, maximum signal selection unit 23, frequency divider 24, second key 25, pulse counter 26, third key 27, shift register 28, the first additional delay element 29, a block of 3 matches, a controllable key 31, an additional driver of 32 time intervals, a decoder 33, a secondary additional delay element H. The device works as follows. The incoming signal through the mixer 1 and the wideband amplifier 2 is fed to the inputs of the channel correlators 17, in which the function of mutual correlation of the incoming signal and reference signals from the generator output 14 of the PRT is calculated. the outputs of channel correlators 17, proportional to the coefficients of mutual correlation of the received and reference signals, makes a decision about the presence or absence of a signal in the analyzed region “To the outputs of the channel correlators 17 is connected pa maximum signal which passes to its maximum input voltage on any of the n-channel correlators. This maximum voltage is applied to the inputs of the main threshold unit 18 and the additional threshold block 19c. The whole signal search process is divided into 3 cycles: the first cycle is a quick view of all the cells of the signal uncertainty body (region). the magnitude of the maximum correlation response; in the second cycle, a two-step signal search is carried out among selected groups of cells; in the third cycle, a two-stage signal search is performed by alternately viewing all the cells.

pulses with latch o The initial state of the counter of 26 pulses is the first inlet of the reset pulse. On the ITEM, a high potential is established at the forward output of the impulse counter 26, which opens the second and third keys 25 and 27, and a low potential is set at the inverse output of the pulse counter 26, closing the matching unit 30, the control key 31 and the lowering threshold in the additional threshold block 19. At the same time, from the output of divider 2 frequency, pulses pass through the open second key 25 to the input of scanner 22, the second input of shift register 28, and also to the fault inputs of channel correlators 17, performed a fast scan of the field for signal uncertainty,. The output voltage from the maximum signal selection unit 23 is compared with the threshold in the additional threshold unit 19, if the maximum voltage is greater than the threshold, then O is written to the shift register 28 as a low potential, if the maximum voltage does not exceed the threshold level, then the register 28 The shear is recorded as 1 high potential. The pulses from the output of the additional threshold unit 19 pass to the input of the shift register 28 through the open third key 27. During the first search cycle, the scan unit 22 passes - pulses, where m is the total, the number of cells, n is the number of parallel-analyzed cells in the device. The capacity of the shift register 28 is also double bits. After passing the pulse, the pulse counter is triggered, the pulse passes to its input is stopped, i.e. the latch circuit is triggered, and the device proceeds to the second search cycle. By the beginning of the second cycle, the numbers of the cell groups in which the signal most likely, the numbers of these groups are reflected by zero bits of the shift register 28. The second search cycle is determined by another state of the pulse counter 2b, while at its direct output

a zero potential is established, closing the second and third keys 25 and 27, and a high potential is established at the inverse output, the opening block 30 matches 5 to one of the inputs, this also opens the control key 31 and the threshold in the additional threshold block 19 increases the output of the divider 2k of the frequency block of the device is stopped, the additional threshold block 19 is disconnected from the shift register 28, the chain of passage of the scanning pulses from the output of the scan block 15 22 through the open yty controllable switch 31 to the primary threshold unit 18,

A scan pulse from the output of scan block 22 passes through 20 open control key 31 to main threshold block 18, which passes it to the output, provided that the signal from the analyzed region is not present. This pulse passes through the first key 21 to the input of the scanning unit 22, to the fault inputs of the channel correlators 17, as well as to the second input of the shift register 28 and the first additional delay element 29. In so doing, the information recorded in shift register 28 is advanced one to the right. If a high level 1 potential appears on the second output of the shift register 28, this corresponds to the fact that the next group of cells should not be analyzed, and there are high potentials on all the inputs of the coincidence unit 30, I After the delay time t at the output of the first additional delay element 29 appears a pulse that passes to the input of block 45 of coincidence and advances information in shift register 28 not 1 bit to the right, resets channel correlators 17 and enters block 22 scanners Neither does the transfer of the data to the analysis of another group of cells and also re-enters the first additional delay element 29, the delay time 141 in the first additional delay element 29 is jj the smallest possible, taking into account transients in the device blocks, which reduces the time search

Then the process is repeated again. If the second output of the shift register 28 reappears 1, the pulse passes through the delay time in the first additional delay element 29 to the input of the coincidence unit 30, advances the contents of the shift register 28, is entered into the scanning unit 22, discharges the channel correlators 17, are AGAIN inserted into the first additional delay element 29. The accelerated scanning process continues until the second output of register 28 fails to reach a low potential corresponding to the possible presence of a signal in this group of cells in the signal uncertainty region. In this case, the coincidence unit 30 closes on one of the inputs and the pulse cycling along the circuit the delay element 29 of the match block 30 is terminated

The device proceeds to a longer signal analysis. Correlation effects accumulate in channel correlators 17, the maximum of them is passed to the output of the maximum signal selection block 23 and compared with a high threshold in the main threshold block 18 and a low threshold in the additional threshold block 19. in the first stage of detection, the signal exceeds the low threshold, then the shaper of 20 time intervals is triggered, which closes the first key 21 for a time equal to the duration of the second stage, If by the end of the second stage si signal is higher than a high threshold and a threshold basically block 18, the passage of the scanning pulse is terminated and proceeds to the tracking mode and extracting information.

If, on the initial detection cycle, a false cell group was selected, a low potential appears at the second output of the shift register 28, and the device switches to the two-stage signal detection mode. However, since the process of rapid circulation of pulses continues for a time comparable to the duration of stage 1 in the second search cycle, this may lead to the hesitancy time of stage 1 being a random value that can be small. at the same time, signal skips will be possible. In order to exclude

This is a harmful phenomenon. An additional driver of 32 time intervals is connected to the first output of the shift register 28, which closes the control key 31 for a time tg approximately equal to (0.6-0i7), where the analysis time of the first stage. In the - The addition of an additional 32 time interval generator increases the time duration of stage 1 slightly (by 10–20), however, it ensures that the high probability of signal detection is preserved for any signal search cycle.

Thus, when occurrence 1 on the first output of the shift register 28, the additional shaper 32 of time intervals is triggered and the appearance of scanning pulses at the output of the first key 21 is delayed until the newly controlled key 31 o is opened

. If a signal is detected, the device is triggered as described. If the signal is not detected at 1 or 2 stages, then the scanning pulse from the fourth output of the scanning unit 22 passes the controlled key 31 and the first key 21, enters the scanning unit 22, and also goes to the second input of the register 28 and the first additional element 29 delays, the contents of shift register 28 are advanced 1 bit to the right, the process repeats again depending on what potential appears at the output of shift register 28. The search process continues either until a signal is detected or until a full registration is cleared 28 shift when all Q states are written out and in all bits of shift register 28 will be 1. This corresponds to the case when the signal, for example, is not present at the input of the search device or when the signal was not detected during the second search cycle. in register 28, the shifts are 1., then the decoder 33 is triggered, and at its output a low potential appears, closing the block 30 for matching one of the inputs. The device proceeds to the third search cycle when all elements of the uncertainty domain are analyzed in the order of alternate viewing. In this case, the potential drop (frost voltage) at the output of the decoder 33

The input of the second additional element 3 is delayed with a delay time 1 ;,, which determines the duration of the search cycle and is selected depending on the requirements of the search system in the interval from T.rdo, where the average search time for an alternate sequential review method j maximum search time with alternate sequential review method.

In the third search cycle, scanning pulses are passed from the fourth output of scanning unit 22. Through a permanently open controlled key 31 to the input of the main threshold unit 18o. The voltage from the output of the maximum signal selection unit 23 goes to the main threshold unit.

18 and additional threshold unit

19o Scanning pulses come with a repetition period equal to the duration of 1 stages. If by the end of the first stage the threshold in the additional threshold block 19 is exceeded, a 20 time interval generator is triggered, which closes the first key 21 and extends the analysis time of this group of cells for the duration of 2 stages . If the threshold in the main threshold unit 18 is exceeded by the end of the second stage, the scanning pulse does not pass through the main threshold unit 18 and the device switches to the signal tracking mode.

If at the stage the threshold in the additional threshold block is not exceeded. 19, the scanning pulse will pass through the open main threshold unit 18, the scan unit 22 will be scanned at the input and will transfer the device to the analysis of the next group of cells. If the threshold in the main threshold unit 18 is not exceeded at stage 2, the next group will also be analyzed the cells.

Claims (1)

But the expiration of the delay time t in the second additional delay element 3 З under the condition that the signal is not detected during this time, the output of the second additional delay element 3 is in accordance with the pulse, which will reset the counter 2b pulses to 11. The tree again goes to the initial first search cycle, the Transition. By analyzing another uncertainty region on 2 and 3 search cycles, the scan pulse is transmitted to the first 6fioKa 22 scan, and the reference sequence is shifted phase, which is done either by closing the first valve 10 (in the normal state is open) or by opening the second valve 13 (in the normal state is closed) for the duration of the required number of pulses of the clock frequency (offset value). also tunable frequency. Controlled local oscillator 6 according to a predetermined tuning program. Operation of automatic frequency tuning scheme consisting of sequentially connected mixer 1, wideband amplifier 2, demodulator 3, narrow-band effort of the it’s body, the lowpass filter 5 and the controlled local oscillator, is carried out in the usual way; the output signal of the low pass filter detector 5 adjusts the frequency of the controlled local oscillator 6, which is fed to the first input of the mixer 1. Thus, in the device, in order to reduce the search time a rational method is used to review the cells of the fct signal, when the cells with the maximum likelihood of finding a signal in them are scanned in the first place, and the remaining cells in the second place. In the initial cycle, the probabilities of finding the signal in the cells are determined and the cells are selected by quickly viewing all the cells or the area of signal uncertainty and comparing the maximum correlation response with the threshold. In the second search cycle, only those cells in which the maximum correlation response, proportional to the probability of the presence of a signal in this group of cells, is greater than the threshold, are viewed. In the third cycle, all the cells of the current sequence are viewed. The device provides a reduction in the average search time. The claims of a noise-like signal searching device comprising a serially connected mixer, a wideband amplifier, a demodulator, a narrowband amplifier, a detector with a low-pass filter (LPF) and a controlled local oscillator, the output of which is connected to the first input of the mixer, the second input of which is the device input, as well as the first OR element, the output of which is connected to the second input of the demodulator and through a serially connected discriminator, correction amplifier, controlled clock generator, the second valve and the second element OR to the input of the pseudo-random signal generator (SRP), whose outputs are connected to the first inputs of the switching valves and the reference inputs of channel correlators, to the signal inputs of which, as well as to the second input of the discriminator, the output of the wideband amplifier, and to the dump inputs channel correlators and the first input of the scanner is connected to the output of the first key, to the first input of which, through the time interval former, the output of the additional threshold block is connected, the input which is connected with the first input of the main threshold unit, the output of which is connected to the second input of the first key, and the outputs of the channel correlators through the switch valves are connected to the inputs of the first OR element, while the output of the controlled clock generator is connected to the first input of the second valve and directly to the second input of the scanning unit, the first output of which is connected to the second input of the controlled local oscillator, and the second and third outputs of the scanning unit are connected respectively to to the second input of the first valve and through the second valve to the second input of the second element OR, characterized in that, in order to reduce the search time, a maximum signal selection block, a frequency divider, a second key and a third key connected in series, a shift register, an additional time driver are introduced intervals and a controllable key, as well as the first additional delay element, a coincidence unit and a serially connected decoder, a second additional delay element and a pulse counter, the direct output of which 13 is connected to the control inputs of the second and third keys, and the output of the controlled clock generator is connected via a frequency divider to the information input of the second key and the second input of the pulse counter, the inverse output of which is connected to the second input of the control key, the control input of the additional threshold unit and the first input of the coincidence unit, to the second, third and fourth inputs of which are connected, respectively, the output of the decoder, the first output of the shift register and the output of the first additional delay element, and the output of the match block is connected to the lane. the first input of the scanner, the input of the first additional delay element and the second input of the shift register 7 hectares, the second output is connected to the input of the decoder, while the output of the second key is connected to the first input of the scanning unit, the fourth output of which is connected to the third input of the controlled key, output which is connected to the second input of the main threshold unit, and the output of the additional threshold unit. connected to the information input of the third key, and the outputs of the channel correlators are connected to the combined inputs of the main and additional threshold units via the maximum signal selection unit. Sources of information., Taken into account in the examination, 1, USSR Author's Certificate No. k35773, class, Н 0 В 1/10, 1973 (prototype).