SU1239877A1 - Device for searching for noise signal - Google Patents

Abstract

This invention relates to a radio technique. Noise immunity increases. The device contains a block of narrow-band interference, consisting of a band-pass filter 3, two mixers 4 and 6, a frequency synthesizer 5; signal generator 7, correlator blocks 8, made identically and consisting of 2 multipliers 14 and integrators of the node combining quadratures of signal 16 ;. block of time compression of signal 9, block of choice on max. 10, threshold block 11, two phase detectors 12, j, phase shifter 13. Block 9 contains a reference oscillator, 3 frequency dividers, a write address counter, 3 switches, an address counter, ADC, two operational blocks, DAC,. Counter in t. In integrators 15. - the resulting values of the correlation convolutions of the reference signal with all the frequency components of the input signal are accumulated. The quadrants of the input signals of the integrators 15 are added to node 16 and fed to block 10, where the max is compared with the threshold in block 11. If the max, the signal from blocks 8 exceeds the threshold, then the device switches to the tuning and receiving mode. 3 hp f-ly, 2 ill. (L Favorite channel number t- signal signal signal kat FIG

Description

The invention relates to a radio communication technique and can be used in broadband radio communication systems.

The purpose of the invention is to increase interference immunity.

FIG. 1 A structural electrical circuit of the noise-like signal searching device is installed; figure 2 - block temporal signal compression.

. The device for searching for a noise-like signal contains a block 1 for protection against narrow-band interference, limiter 2, band i filter 3 i first mixer 4, 5 frequency synthesizer, second mixer 6, generator 7 copies of the signal, correlator blocks 8, block 9 for time signal compression, maximum selection unit 10, threshold unit 11, first and second phase detectors 12 12, phase shifter 13. Corrector unit 8 contains multipliers 14 - and 14, integrators 15, and 15, node 16 of signal quadrature combining. The time signal compression unit 9 contains a reference oscillator 17, the first 18 and second 19 frequency dividers, the write address counter 20, the first and second switches 21 and 22, the counter count 23, the third frequency divider 24, the analog-to-digital converter (ADC) 25, the first 26 and the second 27 blocks of RAM, the third switch 28, the digital-to-analog converter (DAC) 29, the counter 30 per ton.

The device search noise-like signal works as follows

Input mixture X (t) of the last signal and interference, at an intermediate frequency.

f (2k n- 1) -. F,

where F is the clock frequency of the noise-like

signal; k Oh, 1, 2, 3 ... enters the block 9 time compression of the signal.

In block 9, the signal is sampled at a frequency of

F 4 F 1

And consecutive segments of messages of 4 (N + n) durations of 4 (N + n) / F durations are memorized, where N is the length of the transmitted random

sequences; n is the number of correlators in the receiver.

For the first time, 4 N selections of each segment are read m times with frequency

/ s, -f-F ,,.,;

where f-7 / m

and on them m times repeated time-compressed segments of the input signal X (t) with duration T are restored.

The output of the block 9 for temporal compression of the signal is fed to the first input of the first mixer 4, where it is mixed with the output signal of the frequency 5 singler with stepwise varying frequency values.

The step of changing the frequency of the synthesizer is 5 frequencies

,: U F

if - - t,

ha

and the number of frequencies is ha.

The output of the first mixer 4 is filtered by a band-pass filter 3, limited to a fixed level in limiter 2, and mixed with the output signal of a 5-frequency synthesizer. Narrowband interference protection unit 1, consisting of elements 2-6 ,. performs the function of a narrow-band filter-limiter tunable with the uf pin.

Thus, each time a compressed signal segment is mixed at the output of the second mixer 6, one of its frequency components is selected, limited to a fixed level, which goes to the first inputs of the first and second phase detectors 12, and 12J. To the second input of the first phase detector 12, the carrier frequency F-4 oscillates from the second output of the block 9 time compression of the signal, and to the second input of the second phase detector shifted by 90 in the phase shifter 13.

The demodulated frequency components from the outputs of the first and second phase detectors 12, and 12, are respectively supplied to the third and second inputs of blocks of 8 correlators, each of which consists of two quadrature channels containing multipliers 14 and 14, integrators 15 and 15, and a node 16 combining a quadrature signal. At the first supporting entrance. multipliers 14, and 14 copies arrive

pseudo-random sequence from the generator 7 copies of the signal with a clock frequency

F Z F: 4-.

t ss

The fourth (setup) inputs of the 9 correlator blocks 9 receive a reset signal corresponding to the starting points for reading each of the recorded segments of the input signal.

The reset signal of the integrators 15 and 15 simultaneously serves to synchronize the generator 7 copies of the signal. The sequence being formed is connected in phase with the counted signal.

In integrators 15 and 15, the resulting correlation convolutions of the reference signal with all frequency components of the input signal, which are equivalent to the convolution of the reference signal with the input signal, accumulate.

The squares of the input signals of the integrators 15, and 15 2 are added up in the node 16 of the signal quadrature combining and arrive at block 10. Selection by maxi, where they are compared with each other and the maximum of them is compared with the threshold in the threshold block 11. If the maximum signal of the blocks is 8 the correlator exceeds the threshold, the device searching for the noise-like signal goes into the mode of adjustment and reception of information. The phase of the signal is determined in this case by the moment of the beginning of the recording of the next segment of the input signal and the block number 8 correlators with the maximum value of convolution.

Block 9 temporary compression of the signal works as follows. An input noise-like signal with a spectral width d F 2F, fed to the 5th input of the A / D converter 25, is digitized and recorded in the first and second memory blocks 26 and 27. The sampling frequency is selected in accordance with the Krtelnikov 50 theorem and is equal to FO A F. The sampling frequency is formed by dividing the frequency of the reference oscillator 17 in the first frequency divider 18 by 1.

The continuity of signal processing 55 is ensured by the push-pull operation of the first and second memory blocks 26 and 27.

five

J

Yu

f5

20

25,

0

50

five

At a time when samples of the next segment of messages are stored in the first RAM block 26, samples of the previous segment are read from the second RAM block 27 and vice versa. :

In order to ensure the operation of the first and second blocks 26 and 27 of the RAM, the counters 20 and 23 form from the write and read address A, ..., At. Moreover, the write address counter 20 counts q, about 4 (N + n), and the read address counter 23 counts to 4 N. The transfer signal of the write address counter 20. Divided into two in the third frequency divider 24, is the control pulse of the write-read modes. The write signal of the write address counter 20 serves to set the 8 correlator blocks in the noise-like signal searching device, as well as to synchronize the read address counter 23 and the second frequency divider by four. The first and second switches 21 to 22 are used to switch the addresses of the record and, to read out the signals, as well as the chip select signals, the write-read controlled by the direct and indirect signal.

The signals from the first and second I blocks 26 and 27 of the RAM are received via the third switch 28, to the input of the DAC 29, where they are converted to analog form. The time signal compression unit 9 generates a signal by dividing the signal of the reference oscillator 17 by 4 in the second frequency divider 19.

Claims (4)

1. A device for searching a noise-like signal containing a generator of copies of an I signal whose outputs through n correlator blocks are connected to the inputs of a selector unit by a maximum, the output of which is connected to the input of a threshold unit, the code of which is an output of the device, and also a block for narrowband interference , characterized in that, in order to improve the noise immunity, a temporal signal compression unit, two phase detectors and a phase shifter are introduced into it, the first output of the temporal signal compression unit through the narrow protection unit band-fed interference is connected to the first inputs of the first and second phase detectors, and The second output of the signal time compression unit is connected to the first input of the signal copy generator, to the second input of the first phase detector and through the phase shifter to the second input of the second phase detector, whose output is connected to the second inputs of correlator blocks, to the third inputs of which - a new phase detector, while the third and fourth outputs of the time signal compression block are connected respectively to the fourth inputs of the correlator blocks, the second input of the signal copy generator and the second input the narrowband interference protection unit, the input of the time signal compression unit being the device input. , -. 2. The device according to claim 1, about tl and —that is, the narrowband interference protection unit contains a frequency synthesizer and a first mixer, a band-pass filter / limiter and a second mixer, the output of which is the output of the protection unit from narrowband interference, the first and second inputs of which are, respectively, the first input of the first mixer and the input (of a frequency synthesizer, the output of which is connected to the second inputs of the first and second mixers. 3. The device according to claim 1, characterized in that the block of time compression of the signal comprises a reference oscillator, the output of which is connected to the input of the first frequency divider, the first input of the second frequency divider, to the first signal inputs of the first and second switches and the clock input of the read address counter, the outputs of the bits of which are connected via the first switch to the inputs of the first RAM block and directly to the corresponding inputs of the second switch, while the output of the first frequency divider is connected to the second s to the rotary inputs of the first and second switches and clock inputs of the write address counter and analog-digital J5 0 5, Q five 0 five 0 The first converter, the outputs of which bits are connected via the first and second blocks of RAM to the inputs of the third switch, the output of which is connected to the input of the digital-analog converter, and the transfer output of the write address counter is connected to the installation input of the counter D1-. readout, the second input of the second frequency divider and the counter input to m and the clock input of the third frequency divider, the direct output of which is connected to the input of setting the operating mode of the first RAM block and control inputs of the first and third switches, and the inverse output of the third distance switch Frequency .Connected to the installation input of the operation mode of the second RAM block and the control input of the second switch, while the bits of the address of the write address counter are connected to the corresponding inputs of the first com via the second switch to the inputs of the second memory unit, and the output of the read address counter is connected to the clock input of the counter per m, the outputs of which are the fourth output of the time compression signal, the first, the third and third outputs, and the input of which is, respectively, the output of the analog to analog converter, the output of the second frequency divider, the transfer output of the write address counter and the input of an Aloe-Diffractive converter. 4. Device POP.1, characterized in that the correlator blocks are made identically and each of them contains two multiplications — l, the outputs of which, through a corresponding integrator, are connected to the inputs of the combining node of the quadrature signal, whose output is the output of the correlator block, The first, second, third and fourth inputs of which are respectively the combined first inputs of the first and second multipliers, the second input of the first multiplier and the second inputs of the first and second integrators. 744 To SA. 5/5 devices rrri to if, 11 devices JO Along ffcmpoucmOa Fh {)-four Editor A. Sabo Compiled by G. Lerantovich Tehred l.OnEynyk Proofreader V. But ha Order 3410/57 Circulation 624 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 2