SU1104683A1 - Device for restoring reference coherent signal - Google Patents

Abstract

A DEVICE FOR RESTORING A SUPPORT COHERENT SIGNAL, containing two channels connected in input, each of which contains a series-connected low-pass filter, a controlled oscillator. the input mixer, the delay line and the multiplier, the other input of which is connected to the output of the input mixer, the outputs of both channels are connected to the output converter, so that, in order to increase noise immunity, a subtractor is included in each canape between the output of the multiplier and the low-pass filter input A phase shifter is connected in series between the input of the controlled oscillator and another subtractor input, an additional mixer, another input of which is connected to the channel input of the carrier line, and the knife, the other input of which is connected to the output of the additional mixer (Panel mixer, and the output of the generator o is controlled by a frequency divider, the output of which is j output channel.

Description

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The invention relates to a communication technique and can be used in signal processing devices with phase manipulation of 180 ° with one sideband, as well as in signal processing devices with double phase manipulation with quadrature shift of information sequences in radio communication, radiolocation and radio measurement x A device for recovering a reference coherent signal is known, which makes it possible to form a reference oscillation coherent with the carrier for signals with phase manipulation 180 from one side and partially suppressed carrier, made according to the Pistralcorse scheme and contains a series-connected complementary filter, a frequency multiplier of two, Narrowband filter and frequency divider by two. However, the device is characterized by low noise immunity, since the formation of the reference signal occurs from the component of the input signal, The CCrT is located symmetrically with respect to the carrier frequency (i.e., only a part of the input signal energy is used), which is allocated by an additional filter, and, due to the processing of the component of the input signal, additional losses arise. The closest to the proposed technical entity is a device for recovering a reference coherent signal, containing two channels connected to the input, each of which contains a low-pass filter connected in series, an adjustable generator, an input mixer, a delay line, and a polaroid other input connected to the output of the input mixer, the outputs of both channels are connected to the output converter zj. However, the known device also does not provide high noise immunity. The circuit of the invention is an increase in noise immunity. Dp achieve the goal in the device for restoring the reference coherent signal, containing two channels connected in input, each of which contains 32 low-pass filters connected in series, a controlled oscillator, an input mixer, a delay line and a multiplier, another input that is connected to the input of the mixer , the outputs of both channels are connected to the output converter, in each channel between the multiplier output and the low-pass filter input a subtractor is connected, between the output of controlled g A generator and another subtractor are connected in series with a phase shifter, an additional mixer, another input connected to the output of an additional mixer, and a frequency divider connected to the output of the controlled oscillator, whose output is a channel output. In the drawing, a reference coherent signal recovery circuit. The device for restoring the reference | Go coherent signal contains the first channel 1, which consists of the input mixer 2, multiplier 3, delay line 4, subtractor 5, low-pass filter 6, controlled oscillator 7, phase shifter 8, additional mixer 9, multiplier 10, delay line 11 as well as the frequency divider 12, the second channel 13, which consists of the input mixer 14, multiplier 15, delay line 16, subtractor 17, low-pass filter 18, 5 Allowable generator 19, phase shifter 20, additional mixer 21, multiplier 22, delay line 23, as well as divider 24 and pilots at the output transducer 25. The device operates as follows. Phase-manipulated signal with a single phase manipulation for 180 from one side. by the P band (tko5 (2irfHt4LfH) + QUl6in- (21 fHttq.H) The input of the device enters the inputs of the input mixers 2, 14 and additional mixers 9, 21, and the other inputs of the mixers 9, 2 receive signals of C05 21M-1t respectively | 2i. (, From the output of the phase shifter 8 and from the output of the controlled generator 7, and to the other inputs of the mixers 21, 14 cosle tiH + iT / H Mon lv b ..1 from the output of the phase shifter 20 and from the output of the controlled generator 19. Bearing frequency the phase-manipulated signal at the output of mixers 2, 9, 14, 21 frequency is equal to half the clock frequency of the manipulating sequence Thus, the signal at the output of the additional mixer 9 is determined respectively by the extrusion of P (t) co5i7, i -c "-4on, (7i, tt4, lfo and at the output of the mixer 2 by the expression. -P (t) 6ini5M-tFH -4on,) Qtt) coe (tiTt + (fon ,, -4H, at the output of the additional mixer 21 nt) co5iiri t lfong f V Qltbirtl iTi- on -) and at the output of the mixer 14 PitV-sin -fiTitifon -lpHV Q (iVcosC M +), where it, Cf is the carrier frequency and the initial phase of the input phase-shift keyed signal,% n, respectively, the initial phases of the signals generated at the output of controlled oscillators 7, 19, PHl.Qttl are respectively in-phase and quadrature and component manipulating iT.4t information sequence ", respectively, the clock rate, the initial phase of the clock signal, the length of the cycle duration yl sending ma nipuliruyuschey sequence. The signal from the output of the additional mixer 9 is fed to the input of the additional multiplier 10 and through the additional delay line 11 to the second input of the additional multiplier 10, and the output of the input mixer 2 to the first input of the multiplier 3 and through the line 4 to the second input of the multiplier 3. Delay Line x 4 and 11 of the delay is equal to half the length of the manipulated packet. Consequently, the signal at the output of the additional multiplier 10 is determined by the expression Plt1Pli-1 / 1cosiff t (2-Pit | Pit-t / 2) co5 "HS fTt-Tf M / 2 +) QL-tt (2)" cosifi , t | 2-Q t) QU-t / 2lcos 2 iT .-, 2.2tfH-2 (f, bP ((t-1i / 2) sinx (., (n (-i4tg / 2 + 2if -2tion, - Pl-Hz) QUl f x5in7 Tt | 2 + P (t-tfl Q (t) in 23i t-li, a at the output of multiplier 3 PWPlt-W cosirtT / z-PWPa-t / eUosi, 42i M-tT / 2v2tpH-2cfon, QltlQll-e / 2b cosSi t / z -QttlQ ti-g / 2 soe (, t / 2 + (onO-P (t lt- / 2bin "- Plt) Q () sn e-iri. -t-ir) s; n7fr2 / 2- Pit -t / 2 Q ms, n 2 Si I - ff T 12 2h -21 on,) Considering that the sixth and eighth terms in these relations are equal in sum to zero, the signal at the output of the subtractor 5 is determined by the expression 2Pit)) 2) 6; n (2; tt 2tf "-2i {on, -2QUlQU- / 2b (,, V With another stor us, in the spectrum of the product of delayed relative to one another by half cycles of copies information sequence there is a component at a clock frequency K ,, cos (2 | {mb + (fT) Moreover shift sequence information corresponds to the change in poltakta clock phase 180.

Therefore, taking into account that the harmonics at the clock frequency in the spectrum of the product of copies shifted by half a turn, respectively, are the in-phase and quadrature components of the information sequence P (t) P (t - g / 2} and Q (I) q (L - g / 2 ), are in antiphase, and also supposing that the energetics of both components of the clock frequency harmonic is the same, we find that the useful component of the signal at the output of LPF 6 is defined by the expression (Z7i, tt ((2fffTlt2 (f4-2cfon,)).

The beats arising between the carrier oscillation of the phase-manipulated signal at the clock frequency and the harmonics of the clock frequency of the spectrum of the signal, determined by the sum of the products of two copies shifted relative to each other during the poltact, respectively the in-phase and quadrature components of the information sequence, form the discriminatory characteristic at the output of the lower filter 6 frequency in accordance with the expression 51 n () The signal from the output of filter 6 is used to adjust the phase of the controlled oscillator 7. In the sync ronism b1p (2Chp, - (t) 0. Therefore, the phase of the reference oscillation at the output of the generator 7 is equal to cf.

The second channel 13 of the device includes elements similar to the first.

Therefore, its principle of operation does not differ from that considered above. The only difference is that since the value of the frequency of the signal of the controlled oscillator 19 is greater than the value of the carrier frequency of the input phase key. at half the clock frequency, then in synchronization mode, the initial phase of the signal at the output of the controlled oscillator 19 is equal to

OPG Cht / Z.

The signals from the output of the generators 7 and

1.9 through the dividers 12 and 24, the frequencies arrive respectively at both outputs of the output converter 25, which is a multiplier, at the output of which, by means of frequency selection, a reference frequency coherent with the carrier or clock signals is necessary.

Thus, in the proposed device, the energy of the input signal is fully utilized for generating reference signals, and noise immunity, close to the potential, is realized.

Claims (1)

DEVICE FOR RESTORING A REFERENCE COGER SIGNAL, comprising two channels connected at the input, each of which contains a low-pass filter connected in series, a controlled generator, an input mixer, a delay line and a multiplier, the other input of which is connected to the output of the input mixer, the outputs of both channels are connected to the output converter, characterized in that, in order to increase noise immunity, a subtractor is included in each canap between the output of the multiplier and the input of the low-pass filter, between a phase shifter, an additional mixer, the other input of which is connected to the channel input by a delay line, and a multiplier, the other input of which is connected to the output of the additional mixer, and a frequency divider is connected to the output of the controlled generator, the output of which is the channel output . 1 1104683 2