SU763814A1 - Phase meter - Google Patents

Description

one

The invention relates to measurement technology, radio engineering, and is intended for use in receivers of phase-modulated signals and other phase-following systems.

A phase measurement device is known comprising a multiplier, an integrator, a sampling device, a weight averaging device, a phase shifter, and a reference signal generator.

Such a device is characterized by insufficient accuracy of phase measurement when the signal level changes and there is interference in the channel.

A device for measuring the phase of a signal comprising an amplifier, multipliers, a low-pass filter, a nonlinear filter, a phase shifter, a local oscillator, a variable gain amplifier 21 is known.

This device does not provide sufficient phase measurement accuracy when the channel noise level changes.

The aim of the invention is to improve the measurement accuracy in conditions of inconsistency of signal levels and interference,

; 1l of achieving the supplied uejni in the phase meter, containing noc-ic contentedly 5nenn 1; e prier .- city life, amplifier, lower filter, 5 jet lamp and heterodyne, the output of which is connected to the input of the phase shifter, and the amplifier with change power factor, input-: channel control unit, mater, function converter, additional phase shifter and double-sided limiter. At the same time, the output of the local oscillator is connected to a single one: from the amplifier inputs with a variable gain coefficient, the output of which is connected to the first input from the mmator, the second input of which is connected to the output of the phase shifter, and the output of the adder through a series-connected additional phase switch; connected to the input of the multiplier, the second input of which is connected via the channel state control unit to the first input of the function converter, the second input of which is connected to the output of the low-pass filter, and its The output is connected to the control input of the amplifier with a variable coefficient.

30 amps.

The block diagram of the phase meter is shown on the drawing.

Phase meter contains multiplier 1, amplifier 2, frequency filter 3, jet lamp 4, local oscillator 5, phase shifter 6, adder 7, additional phase shifter 8, limiter 9, channel state control unit 10, function converter 11, variable coefficient amplifier 11 gain

The phase meter works as follows.

The signal from the output of the linear part of the receiver is fed to the multiplier 1 and the channel condition control unit 10, the output of the multiplier relieves voltage depending on the phase difference between the received signal and the reference oscillation, and also depending on the signal level and noise at the output of the linear part of the receiver

Increasing (decreasing) the signal / cd ratio and correspondingly small phase error, increasing (decreasing) 1 rutiz of the decriminal characteristic makes it possible to increase the accuracy of the phase measurement :. The control of the discriminative characteristic gives an introduction to the structural scheme, complete with 1 glue eLEg-izngov and the connection between them. If you break the connection between the internal control modules of the control input of the amplifier 12 with a change in the gain and the output of the function converter 11, the remainder of the shells implements the functions of the standard cxeMini FLP with a discrimination characteristic proportional to q /; sine carrier sine phase difference of the input signal and the reference generator 5.

The phase measurement error signal amplified by amplifier 2 from low-pass filter 3 is converted by a jet lamp 4 and a local oscillator 5 into a phase of the reference oscillation, which through phase shifter 6 enters the adder 7. The same reference oscillation is fed to the other input of the adder, and its amplitude / is divided by the pitch, sn-mm-mm from the output of the function converter 11,

The functional dependence of the voltage — at the output of the function converter — on the signal characterizing the state of the channel and on the error signal is selected in accordance with the requirements for changing the discriminatory characteristic. At the output of the adder 7, the phase of the reference oscillation is determined by the selected functional dependency. The phase shift in the additional phase shifter 8 is chosen so that when the phase measurement error is fixed, the signal and the support oscillation at the inputs of multiplier 1 are phase-shifted by 90. The two-way amplitude limiter 9 eliminates parasitic variations in the amplitude of the reference oscillation.

The functional dependence of the converter can be specified, for example, in the form f (h, E, t)) - (t), where h2 (t) is the signal-to-noise ratio at the output of the linear part of the receiver at a given moment in time — a signal characterizing the state of the channel; (t) is the phase measurement error signal. Then, at time interval At, the phase measurement error at the output of the low-pass filter 3 is described by the expression

(t itl 5 n arctg e (t) (itl

EiiUl ii

TfT e Itbh tTr

This one is essentially the discriminatory characteristic of a device for phase measurement.

The information about the phase of the reference oscillation can be entered from the output of the filter at lower frequencies and is an estimate of the difference between the received and reference signals.

Claims (1)

one. . Stiffler The theory of synchronous communication, §pyp. 3M.,. References 1975, p. 124, 2o Tikhonov V.I. Statistical radio engineering, M, Soviet Radio, 1966, p. 534,