SU1197136A1 - Receiver of phase-shift keyed signals - Google Patents

Abstract

A RECEPTION PHASE-MANIPULATED SIGNAL, containing a series-connected first adder, a correlator, a phase detector, a low-pass filter, a control element, a controlled oscillator, a phase shifter and a mixer, the second-connected second adder, a phase detector, a low-pass filter, a control element and controlled oscillator, serially connected second correlator, third adder and third filter lower. These are the frequencies, the third control element connected in series, the third controlled generator and the pseudo-random sequence generator, and the third correlator, second phase shifter and modulator, whose output is connected to the subtracting input of the second adder, the summing input of which is connected to the summing input of the first adder and is the receiver input, and the output of the first controlled generator is connected to the second input of the first phase detector, the output of the second controlled generator is connected to the second m input of the second phase of the detector and through the second phase detector with subtracting input of the first adder, the output of the mixer is connected to the first input of the second correlator and through the third correlator to the subtracting input of the third adder, and the output of the first adder is connected to the second input of the mixer, while the output of the first phase shifter is connected to the first input of the modulator, and the first, second and third outputs of the pseudo-random sequence generator are connected respectively to the second inputs of the modulator and the first correlator, second The second input of the third correlator and the second input of the second correlator, characterized in that, in order to (L increase the noise immunity of reception with nonlinear phase distortions of the signals J), the sequentially connected quadratic dedector, the fourth low pass filter and the threshold unit, sequentially connected fourth are entered into it a correlator, an envelope detector, a fifth co-low pass filter, and an amplifier, connected in series by a fifth correlator, a fourth adder, a third Indoor phase detector, a sixth lower filter frequency and the first key, serially connected frequency multiplier and bandpass filter, second key and serially connected delay block and sixth correlator whose second input is connected to the output of the first adder, the first input of the fifth correlator, the input of the delay block and the first input of the fourth correlator whose second input is connected to the second output of the delay unit, the third output

Description

which is connected to the second input of the fifth correlator, and the inputs of the quadratic detector and frequency multiplier are connected respectively to the outputs of the first correlator and phase shifter, the output of the band-pass filter is connected to the second input of the third phase detector, the output of the sixth correlator is connected to the subtracting input of the fourth adder, and the output of the amplifier is connected to the second input of the threshold unit, and the output of the third filter of n-frequency is connected to the signal input of the second key, the inverse and direct outputs of the threshold unit connected to the control INPT4, respectively, of the first and second keys, the outputs of which are connected to the input of the third control element.

The invention relates to telecommunications and can be used in digital broadband radio communication systems in the presence of nonlinear phase distortion of signals.

The purpose of the invention is to increase the noise immunity of reception with nonlinear phase distortion of signals.

The drawing shows a structural electrical circuit of the receiver of phase-shifted signals.

. The receiver of phase-shifted synols contains the first adder 1, the correlator 2, the phase detector 3, the low-pass filter 4, the control element 5, the controlled oscillator 6, the phase shifter 7 and the mixer 8, the second adder 9, the phase detector 10, the low-pass filter 11, the control element 12 and the controlled generator 13, the second correlator 14, the third adder 15, the third 4 "low pass 1, the third control element 17 and the third controlled oscillator 18, the generator 19 is a pseudo-random sequence, the third correlator 20, the second phase shifter 21 module torus 22, and also contains a quadratic detector 23, a fourth lowpass filter 24, a threshold unit 25, a quaternary correlator 26, an envelope detector 27, a five lowpass filter 28, an amplifier 29, a fifth correlator 30, a fourth adder 31, a third phase detector 32, sixth lowpass filter 33, first key 34, frequency multiplier 35, band pass filter 36, second key 37, delay block 38 and sixth correlator 39.

The receiver of phase-shifted signals works as follows.

The input signal is fed to the summing inputs of the first and second adders 1 and 9. From the output of the first adder 1, the input signal is fed to the first input of the first correlator 2, to the second input of which

0 a p – 1 bit of a pseudo-random generator 19 is supplied. The first correlator 2 contains a multiplier of the input and reference signals and a bandpass filter that inputs the signal into. the carrier frequency that arrives: at the first input of the phase detector 3 and the input of the quadratic detector 23. At the second input of the first phase

0 of detector 3, a carrier signal is generated by the first controlled oscillator 6. In the event of a mismatch between the frequencies and phases of the input and reference signals, a control signal is received at the output of the first phase detector 3, which through the first low-pass filter 4 and the first control element 5 performs phase adjustment

0 is the frequency of the first controlled oscillator 6 for the frequency and phase of the input signal carrier. The phased carrier signal is shifted by the first phase shifter 7 by P / 2 and fed to the reference inputs of the mixer 8, the modulator 22 and the multiplier for 35 hours. tots for two. In the case, if the signal is proportional to the square of the amplitude of the signal at the output of the correlation part of the receiver (i.e.

the first correlator 2), formed by a quadratic detector 23 and the fourth low-pass filter 24 and arriving at the first input of the threshold unit 25, exceeds the signal acting on its second input, the voltage from the direct output of the iporoBoro block 25 opens the second key 37. In this case, the first key 34 is locked by a voltage acting on the inverse output of the threshold unit 25. At the output of the mixer 8, a video signal of a random random sequence is generated, which is fed to the first inputs of the second and third correlators 14 and 20, to the second inputs of which signals from outputs 11 -2 and n bits of the generator 19 of a pseudo-random sequence are received. The signals from the outputs of the correlators l4 and 20 are fed to the summing and subtracting inputs

third adder 15. Depending on I

From the delay sign of the pseudo-random sequence of the input signal relative to the signal generated by the pseudorandom sequence generator 19, the magnitude and sign of the error signal at the output of the third adder 15 changes. The error signal opens the second key 37 and the third control element 17 through the third low-pass filter 16 on the third controlled oscillator 18. Thus, the delays of the signal of the pseudo-random sequence generator 19 relative to the input signal are eliminated. The video signal from the output h -1 of the discharge of the generator 19 of a pseudo-random sequence is fed to the signal input of the modulator 22, which modulates the carrier frequency from the output of the phase shifter 7 and forms phase-shifted,

arriving at the subtracting input of the second adder 9, where it is subtracted from the input signal. In the case of an additive sinusoidal interference input to the receiver, the latter is allocated at the output of the adder 9 and is fed to the first input of the second phase detector 10, the second input of which receives a sinusoidal signal generated by the second controlled oscillator 13. The second phase distant 197136

Spectrum 10, low-pass filter 11 and control element 12 carry out an auto-triple frequency of the second controlled oscillator 13. 5 under the frequency of sinusoidal interference. This signal is shifted in phase by P / 2 by the second phase shifter 21 and is fed to the subtracting input of the first adder 1, where

10, the compensation of the sinusoidal noise and the exclusion of its influence on the tracking circuit of the signal parameters. The signal from the output of the first adder 1 is fed to the input of block 38 of delay 5 ki and to the signal inputs of the fifth and sixth correlators 30 and 39, to the reference inputs of which are supplied signals from the taps 38 of the delay 38, and these taps are made so

2Q that the delay between the signals at the taps is 2, where is the length of the element of the pseudo-random sequence. The signals from the outputs of the correlating tori 30 and 39 are served

25 to the summing and subtracting inputs of the fourth adder 31.

The difference signal is fed to the first input of the third phase detector 32, to the second input of which a signal arrives at the doubled frequency of the carrier, obtained using frequency multiplier 35 by two and band-pass filter 36. The error signal from the output of phase detector 32 through the sixth low-pass filter 33

 arrives at the signal input of the first key 34. The fig input of the fourth correlator 26 receives a signal from the retraction of the delay block 38 with a delay time ifS relative to

40 signals taken from his two other taps.

The fourth correlator 26 forms a hail on the carrier frequency, which through the envelope detector 27,

 fifth low pass filter 28 and

amplifier 29 with a gain factor of 1/2 is applied to the input of threshold unit 25.

Auto torrent signal from exit

 amplifier 29 is compared with the output voltage of a quadratic detector 23, filtered by a fourth lowpass filter 24. If as a result of phase spectrum distortion

55 of the input signal, the level of its convolution with the reference sequence becomes lower than the level of convolution in the autocorrelator torus (insensitive to phase distortions of the input signal), then the signals from the outputs of the threshold unit 25 will switch the first and second keys, i.e. the first key 34 is closed, and the second key 37 is opened. In this case, the third control generator 18 will begin to be controlled by an error signal from the output of the third phase detector 32..

With the improvement of radio propagation conditions, the convolution voltage from the output of the correlation part

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the receiver is increased and after the level set by the autocorrelator is exceeded, the receiver again switches to the tracking control mode by the correlation processing circuit of the input signal.

Thus, an increase in the noise immunity of the reception of the phase-shifted signals is achieved in 10 cases of distortion of the phase spectrum of signals caused by the nonlinear dispersing properties of the radio channel.

Claims (1)

A PHASOMANIPULATED SIGNAL RECEIVER containing a first adder, a correlator, a phase detector, a low-pass filter, a control element, a controlled oscillator, a phase shifter and a mixer, a second adder, a phase detector, a low-pass filter, a control element and a controlled oscillator connected in series a second correlator, a third adder and a third low-pass filter, connected in series with a third control element, a third controlled generator and a gene a pseudo-random sequence ator, as well as a third correlator, a second phase shifter and a modulator, the output of which is connected to the subtracting input of the second adder, the summing input of which is connected to the summing input of the first adder and is the input of the receiver, the output of the first controlled generator connected to the second input of the first phase detector, the output of the управляемогоτογ horn controlled generator is connected to the second input of the second phase detector and through the second phase shifter with a subtracting input of the first adder, the output with the mixer is connected to the first input of the second correlator and through the third correlator to the subtracting input of the third adder, and the output of the first adder is connected to the second input of the mixer, while the output of the first phase shifter is connected to the first input of the modulator, and the first, second and third outputs of the pseudo-random sequence generator are connected, respectively with the second inputs of the modulator and the first correlator, the second input of the third correlator and the second input of the second correlator, characterized in that, in order to increase the noise immunity for receiving non-linear phase distortion of the signals, a series-connected quadratic dedetector, a fourth low-pass filter and a threshold block, a series-connected fourth correlator, an envelope detector, a fifth low-pass filter and an amplifier, a series-connected fifth correlator, a fourth adder, and a third phase detector are introduced into it , the sixth low-pass filter and the first key, the frequency multiplier and the band-pass filter connected in series, the second key and the back unit connected in series arms and the sixth correlator, the second input of which is connected to the output of the first adder, the first input of the fifth correlator, the input of the delay unit and the first input of the fourth correlator, the second input of which is connected to the second output of the delay unit, the third output of which>> SU 1197136 is connected to the second input of the fifth correlator, and the inputs of the quadratic detector and frequency multiplier are connected respectively to the outputs of the first correlator and phase shifter, the output of the bandpass filter is connected to the second input of the third phase detector, the output is of the correlator is connected to the subtracting input of the fourth adder, and the amplifier output is connected to the second input of the threshold block, while the output of the third low-pass filter is connected to the signal input of the second key, the inverse and direct outputs of the threshold block are connected to the control inputs of the first and second keys, respectively the outputs of which are connected to the input of the third control element.