SU779901A1 - Device for measuring phase shift in phase-manipulated signal - Google Patents

Description

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The invention is intended for use in radar and communication technology, where phase shift keyed signals (FMN) are widely used.

A device for measuring the phases of a phase shift key is known, based on the use of several parallel-connected channels Ij.

The disadvantage of it is low sensitivity ..

Another device is known which is a device for coherent reception of FMN signals 2j A necessary condition for coherent reception of FMN signals is the presence of a reference voltage at the receiving point, which has a constant phase and a frequency equal to the frequency of the received signal. In the device, the reference voltage is obtained from a coherent heterodyne, the synphase and synchronization of oscillations is provided by the phasing device.

The device contains an intermediate frequency amplifier (IF). Phasing device, coherent local oscillator, phase detector.

The disadvantage of the device is relatively low sensitivity when measuring small phase shifts.

In the received FMN signal. This is due to the inaccuracy of the phasing of the coherent local oscillator, which does not provide the necessary synphasic and synchronous oscillations, since its phase and frequency change under the influence of a number of destabilizing factors.

The aim of the present invention is to increase the sensitivity with

10 measurements of small phase shifts. The goal is achieved by the fact that the device for measuring the phase shift in the phase-shift keyed signal, containing sequentially

"5 connected intermediate frequency amplifier and phase detector, an additional phase detector and a sequential multiplier of voltage and narrowband are introduced in series

2Q filter, the OUT of which is connected to the reference inputs of the phase detectors, the first input of the voltage intermitter is connected to the output of the phase detector, the second input to the second OUTPUT of the intermediate amplifier 4acTOTk, and the output to the information INPUT of the additional phase detector.

The drawing shows a structural

Claims (2)

30 | device diagram. It contains amplifier 1 intermediate frequency (IFA), multiplier 2 voltage., Narrowband filter 3 phase detectors (PD) 4 and 5. In the device, the first output of AMO 1 is connected to the information (signal) input of the phase detector 4, the output of which is connected to the first voltage multiplier 2 input, and the second IFA 1 output is connected to the second input of voltage multiplier 2, whose output 1 is connected to the signal input of the phase detector 5 and to the input of the narrowband filter 3, the output of which is connected to the reference inputs of the phase detectors, 4 and 5, Const The solution works as follows. . The received FMN signal S (t) Uc | cos (Sho t + TL / 2 l + V (t) J + ((t) + P) UcV (t) cps (u) ct4 + c). where Ф (t) is the manipulated component of the phase / representing the law of phase manipulation, and Fm (t) Const with K (K + 1) t and changes abruptly with, i.e. at the boundaries between adjacent elementary premises (K, 1.2N-1); Tg) is the duration of the elementary parcels; N is the number of elementary parcels; V (t) is the direct current parcel (modulating code); It comes from the first output of the overclocking unit 1 to the information input of the PD 4 and the second output of the overclocking unit 1 — the second input of the voltage multiplier 2. The detected signal Up; (t) Up cosf-P Ct) from the output of the phase detector 4 is fed to the first input multiplying the voltage multiplier 2. As a result of multiplying the signal and the FMN signal at the output of the voltage multiplier 2, the resulting oscillation is formed as a combination of harmonic oscillation and FMK signal with a doubled value of the manipulated component of the phase U (t) U (t) + U. ( t) K Up U Cosutf +) (t)}. where k is the transmission coefficient of the first resident. Harmonic oscillation, where U (t) U, t, .Uc. Allocated to narrowband filter 3 and fed to the reference inputs of phase detectors 4 and 5. FMN signal-with a double value of the manipulated phase component and harmonic oscillation Uj (t) UQ with a) c t + 24) (t) +00 s lOc t } arrive at the information input of the phase detector 5, to the reference input of which a harmonic oscillation enters and (t) Uocos Bc t. As a result of multiplying these oscillations in the phase detector 5, a detected signal appears at its output with a double value of the manipulated component Up, (t) (t). Thus, the phase shifts in the QPSK signal measured by the phase detector 5 are 2 times larger than those of the input signal. Apparatus for measuring the phase shift in a phase-manded signal containing a series-connected intermediate frequency amplifier and a phase detector, characterized in that, in order to increase sensitivity in measuring small phase shifts, an additional phase detector and a series-connected multiplier of the strains and a narrowband filter are introduced, the output of which is connected to the reference inputs of the phase detectors, with the first input of the voltage multiplier connected to the output of the phase detector Ktora, the second input - with the second output of the intermediate frequency amplifier, and the output - with the information input of the additional phase detector, the vector. Sources of information accepted in the attention during the examination 1. Author's certificate of the USSR No. 283399, G 01 R 25/00, 1968. 2. Klyuev NI Informational basis of messaging. M., Soviet Radio, 1966, p. 134.