SU1146811A1 - Device for transmission and reception using noise signals - Google Patents

Description

The invention relates to communication technology and can be used to transmit discrete information in multipath communication channels with variable parameters.,; A device for transmitting and receiving discrete information over multipath channels is known, which uses phase-shift keyed signals and consistent reception with the accumulation of rays L. The disadvantage of this device is low noise immunity in channels with variable parameters at a high information transfer rate. The closest in technical sense to the invention is a device for transmitting and receiving noise-like signals, containing on the front side a clock-and-pulse generator, the output of which is connected to the generator input. pseudo-smooth sequence (SRP), connected in series by a generator carrying frequency, phase shifter by 90, psr:, 1st multiplier and adder, a. also the GAO Next connected phase manipulator, the information input of which is connected to the information source, and a second multiplier, the input of the phase manipulator Fora is connected to the output of the carrier frequency generator, and the output of the second multiplier is connected to the second input of the adder, whose output is connected to the input of the transmitting antenna, and on the receiving side - punishment signal processing and receiving antenna 2. . However, the known device has a low noise immunity in a multipath channel, due to the decision on the transmitted symbol on only one of the incoming beams, while the signals from other paths interfere with the decision making. The purpose of the invention is to improve the noise immunity. Discretely transmitting information in multipath conditions. The goal is achieved by the fact that in a device for transmitting and receiving signals with a similar signal containing a clock generator on the transmitting side whose output is connected to the input of a pseudo-random sequence generator (PSP), serially connected carrier frequency generator, phase shifter by 90, first multiplier and adder, as well as serially connected phase manipulator, whose information input is connected to the information source, and the second multiplier, with input phase manipulator is connected to the output of the carrier frequency generator, and the output of the second multiplier is connected to the second input of the adder, the code of which is connected to the input of the transmitting antenna, and Receiving side - signal processing channel and receiving antenna, are entered on the transmitting side (M-1) of the PSP generators, the switch, the control unit and the delay line, the outputs of all PSP generators are connected to the corresponding inputs of the switch, the output of which is connected to the second input of the second multiplier and through the delay line to the second input of the first multiplier, the output of the clock pulse generator being connected to the combined inputs of the SRP generator and to the input of the control unit, the output of which is connected to the control input of the switch a, and on the receiving side an adder, a control unit, () signal processing channels, each of which contains a series-connected matching filter, a delay line, a phase detector, a drive and a resolver unit, with the other input of the phase detector connected to the output of the matched filter, and the inputs all channels of signal processing are combined and connected to the output of the receiving antenna, as well as to the input of the control unit, the outputs of which are connected to the combined control inputs of the accumulator and the decisive block of each channel signal processing, and the outputs of the blocks of all signal processing channels are connected to the corresponding inputs of the adder, the output of which is the output of the device. FIG. 1 shows a structural electrical circuit of a device for transmitting and receiving noise-like signals; in fig. 2 is a structural electrical circuit of the control unit 17; in fig. 3 - timing diagrams for the operation of the device. The device for transmitting and receiving noise-like signals on the transmitting side contains a generator of 1 clock pulses, a generator of 2 PSPs, a control unit 3, a carrier frequency generator 4, a phase shifter 5 of 90 °, a first multiplier 6, an adder 7, a phase manipulator 8, a second multiplier 9, switch 10, delay line 11, and on the receiving side matched filters 12, delay lines 13, phase detectors 14, accumulators 15, decision blocks 16, control Christmas 17, adder 18. Control block 17 contains matched filter 19, amplitude detector 20, block 21 tani, one-shot 22, delay line 23. The device works as follows. The clock generator 1 generates the clock pulses necessary for the operation of the 2 PRS generators, the number of which when using binary transmission with opposite signals is determined by the relation - if - where. M - "the number of SRP generators; Tr - multipath interval: Tj. - the duration of the information signal. Generators 2 SRP produce binary sequences that form an SRP ensemble with minimal mutual interference. The sequence of connection of the bandwidth bandwidth is chosen so that during the time of multipourage, each bandwidth is used no more than once. In this case, the operation algorithm of switch 10 reduces to the alternate connection of all generators 2 memory bandwidths at the times corresponding to the beginning, - to a pseudo-random sequence. The control unit 3 is a modulo M counter. The cyclic sequence of all signals of the selected SRP ensemble, received at the output of the switch 10, goes to the second multiplier 9, to the first input of which the carrier frequency is received, which is phase-controlled by the transmitted information. The same sequence through the delay line 11 is fed to the first multiplier 6, the carrier frequency arrives at the first input of the superhistor, phase shifted by 90 by the phase shifter 5. The delay time 114 ki of the delay line 11 is selected from the ratio. , (2) where btc | - the phase correlation interval of the signal that has passed through a multipath channel. Since the signals at the input of the adder 7 are in quadrature, the peak factor of the signal transmitted to the communication channel is 1. This allows the use of transmitter power. The signal formed on the transmitting side and passed through the multipath communication channel is fed at the receiving side to the combined inputs of the matched filters 12 and the control unit 17. Each of the matched filters 12 is matched with a corresponding pseudo-random sequence. Thus, the received signal is divided in form into M parallel signal processing channels, each of which processes signals transmitted by a particular pseudo-random sequence. The signal from the output of matched filter 12 enters the phase detector 14, which performs the information phase difference. As a reference signal for the phase detector 14, a signal from the output of the same matched filter 12 is used, which is delayed in the delay line 13 by a time equal to the delay time entered on the transmission side. By introducing on the transmission side the necessary number of generators 2 ,. The SRP at the output of the phase detector 14 signals from adjacent premises are separated in time by at least the duration of the multipath time. Therefore, in the signal processing, intersymbol interference does not occur. This allows for the accumulation of all incoming rays in the multipath interval in the accumulator 15, which can be implemented as an integrator with a reset. At the moment of the end of accumulation, the decisive block 16 performs the signal reading at the output of the accumulator 15 and makes a decision on the transmitted information according to the sign of this count. Solutions from the outputs of all decision blocks 16 are combined by adder 18 and received to the recipient of information. The control unit 17 generates the signals necessary for the operation of the accumulators 15 and decisive 16, In the case of accumulation of beams in the interval (M-1) T, the control unit 17 can be implemented according to the block diagram given in F1 | g, 2, while 1) lines 23 delays. The delay in each of the delay lines 23 is equal to the duration of the information symbol. The pulse duration produced by the one-shot 22 is equal to (M-1) T. To simplify the control block 17, instead of the matched filter 19, one of the matched filters 12 can be used.

The timing diagrams shown in FIG. 3 are constructed for the case of using three pseudo-random sequences and the presence of four separable rays in the communication channel without noise for the case of using PSP ensembles with ideal correlation properties,

where 1 - part of discrete information to be transferred;

2- response at the output of the matched filter of the first processing channel (the response to the reference signal is not shaded);

3- response at the output of the delay line of the first channel;

4- response at phase out

the detector of the first channel;

5- signal at control inputs

accumulator and decision circuit of the first channel;

6- drive output

the first channel;

7- output signal

schemes of the first channel;

8- response at the output of the matched filter of the second processing channel;

the output signal of the phase detector of the second channel;

drive output signal

the second channel;

output signal decisive

second channel circuits;

the response at the output of the matched filter of the third processing channel;

phase output signal

third channel detector;

drive output signal

the third channel;

output signal decisive

third channel circuits;

signal at the output of the adder.

In the proposed device, by introducing on the transmitting side additional generators 2 SRPs for reception, protective time intervals are formed in each of the processing channels. Not less than the duration of the information symbol, therefore intersymbol interference does not occur. In addition, in each processing channel, accumulation of all incoming rays on a multipath interval is possible.

Thus, the proposed device allows to increase the stability of the transmission of discrete information through multipath channels, with variable parameters and the Doppler effect with durations of information symbols that are shorter than multipath time. This makes it possible to increase the speed of information transfer and thereby increase the efficiency of using the frequency band allocated to the communication system.

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Claims (1)

TRANSMISSION AND RECEIVING DEVICE BY NOISE-SIMILAR SIGNALS ', containing / on the transmitting side a clock pulse generator, the output of which is connected to the input of the pseudo-random sequence generator, serially connected carrier-frequency generator, phase shifter 90 °, the first multiplier and adder, as well as series-connected phase a manipulator, the information input of which is connected to an information source, and a second multiplier, the input of the phase manipulator being connected to the output of the carrier frequency generator, and the output the second multiplier is connected to the second input of the adder, the output of which is connected to the input of the transmitting antenna, and on the receiving side there is a signal processing channel and a receiving antenna, characterized in that, in order to increase the noise immunity of transmitting discrete information in multipath conditions, introduced on the transmitting side (M-.1) of the pseudo-random sequence generators, a switch, a control unit and a delay line, and the outputs of all pseudo-random sequence generators are connected to the corresponding inputs to switch, the output of which is connected to the second input of the second multiplier and through the delay line to the second input of the first multiplier, and the output of the clock generator is connected to the combined inputs of the generators. pseudo-random sequence and to the input of the control unit, the output of which is connected to the control input of the switch, and on the receiving side, the adder, control unit, ί (M-1) signal processing channels, each of which contains ^ sequence. tightly connected matched. a filter, a delay line, a phase detector, a drive, and a decision unit, the other input of the phase detector connected to the output of the matched filter, and the inputs of all signal processing channels combined and connected to the output of the receiving antenna, as well as to the input of the control unit, the outputs of which are connected to the combined control inputs of the drive and the decision block of each of the signal processing channels, and the outputs of the decision blocks of all signal processing channels are connected to the corresponding inputs of the adder, the output of which is the output m devices. _ · ..