SU739433A1 - Device for measuring phase shift - Google Patents

Description

one

The invention is sug- gested by a phase-measuring technique, which can be used to measure the phase of the modulating oscillation amplitude-modulated or. phase modulated signals of group lag time meters with a high concentration of energy across the spectrum, as well as in other radio-technical devices, using similar signals.

A phase meter is known that includes a frequency conversion device and an automatic phase self-tuning unit.

A disadvantage of the known device is the impossibility of measuring the phase voltage of the modulated input signal.

Closest to the proposed device for measuring the phase shift, containing the input mixer, the first IF, the second mixer, wideband IF, phase-locked loop on the carrier, phase detector, frequency synthesizer, modulator and phase meter.

2

Disadvantages / prototype - significant component of the amplitude-phase error, lack of sensitivity and complexity.

The aim of the invention is to reduce the amplitude-phase error, increase sensitivity and simplify.

This goal is achieved by the fact that, in a device for measuring the phase shift, comprising a series-connected mixer, an intermediate frequency amplifier, an amplitude detector and a phase meter, a reference frequency generator, a phase self-tuning unit, one of the inputs of which is connected to the output of the reference frequency generator, and the other - with the mixer, the modulation reference frequency generator, the additional mixer and the modulator, one of which is connected to the output of the phase locked loop of the frequency and the output from orym input mixer, the modulation frequency of the reference oscillator output connected to a control input of the modulator and one of the additional V.HODOV mixer and the output of the latter is connected to a second input of the phase meter .; FIG. 1 shows a structural electrical circuit of the device of FIG. 2 shows the spectra of signals. The device contains a mixer 1, an intermediate frequency amplifier 2, an amplitude detector 3, a phase meter 4, a phase-locked loop S, a modulator 6, a modulation frequency generator 7, an additional mixer 8, and a frequency generator 9.. The device operates as follows. Mixer 1 receives an input signal, modulated in phase with frequency f, and a signal of modulator 6, modulated by an external voltage. of the generator 7 of the reference modulation hour, which is arbitrarily close, but does not coincide with the possible values. 2.- a, 2 b. The carrier tpTa of the modulator signal, received by the phase-locked loop unit 5 on the carrier, monitors the carrier frequency variations of the input FM modulator and; therefore, the HecyBiiaH frequency of the signal on the drive mixes ILI 1 (intermediate frequency f) is constant. The cueitpp signal at the output of the mixer 1 is shown in FIG. 2 in. The central spectrum (Fig. 2g) of the output mixer output expresses the amplification of intermediate frequency 2, whose resonant frequency is equal to the difference aedymftx of the frequencies of the input FM signal and modulator 6, and the bandwidth is close to 2 (f - fLonb the intermediate frequency in the proposed device is h times smaller than the width (m - paths) of the spectrum of the intermediate frequency oscillations of the known device. From the output of the intermediate frequency 2 amplifier, the normalized amplitude of the trigger signal goes to detector 3 output. The same voltage of the detector with the frequency Tn is the law of changing the phase of which one very well corresponds to the law of changing the phase modulation of the Suitable ciSftiana DEVICE, is fed to one input of the phase meter, to another its input the reference voltage of the same mixer 8 arrives. The modulator 6 is made according to the well-known scheme, using vigeys to form

  .-r-: "; ih-j: .- i. FM signals. It contains a balanced modulator, at the level of which the carrier frequency is suppressed, the phase shifter, through the main carrier frequency, arrives at the input to the amplifying o amplifier, and the amplification signal, with an adjustable gain factor. At the output of the motor, only three spectral components have a significant amplitude: carrier and two side components, upper and lower, separated from the carrier by the frequency. Preus Lotren; the possibility of adjusting the amplitude and phase ratio in: the output signal of the modulator using an adjustable phase shifter and signal amplifier -Rcd. By adjusting the phase relationships in the modulator output signal, it is possible to transform the input FM or AM signal into an AM or FM signal of an intermediate frequency. The best result was obtained at the AM intermediate frequency signal, since the intermediate frequency FM signal contains spurious amplitude modulation, which is the cause of the phase error occurring in the FM signal demodulator ... Application of the modulation reference frequency mop in the preferred device but does not coincide with the possible values of the frequency modulation of the incoming signal, it limits the spectrum of the cope-i intermediate-frequency bath and, consequently, the bandwidth of the intermediate-frequency amplifier you're in. time. At the same time, caMbHvt increases the amplitude-phase error in the amplitude-phase error arising in the amplitude normalizer and increases the signal-to-noise ratio at the input of the demodulator. In the case of using the device in the group lag time meter, the relation ratio is f .. 5 4 --10-S and 3 a b. Formula 8. phase device A device for measuring the phase shift, containing after-included mixer, interceptor frequency, amplitude detector n phase meter, reference frequency generator, phase-locked loop, one of the inputs of which is connected to the top: one reference frequency generator, and the other to the mixer top input, reference modulation generator, additional mixer and modulator, one of ahodov which is connected to the output of the phase locked loop, and the output is connected to the second input ck {capacitor, characterized in that

There is a reduction in the amplitude of the acoustical error, an increase in sensitivity and control, the modulation reference generator is connected to the control input of the modulator and one of the inputs of the Additional mixer, and the output of the latter is connected to the second input of the phase meter.

Claims (1)

Claim A device for measuring the phase shift, which contains a ₅₅ 'mixer, an intermediate frequency amplifier, an amplitude detector and a phase meter, a reference frequency generator, a phase locked loop, one of the inputs of which is connected to the output.5 739433 6. the house of the reference frequency generator, and the other with the mixer input, the reference modulation frequency generator, an additional mixer and a modulator, one of the inputs of which is connected to the output of the phase-locked loop, and the output - with the second input of the mixer, characterized in that, with In order to reduce the amplitude-phase error, increase sensitivity and control, the output of the reference modulation frequency generator is connected to the 5 control input of the modulator 'and one of the inputs of the Additional mixer, and the output of the latter is connected to the second input of the phase meter. Phil 1 ЦНИИПИ Order 2916/39 Circulation 1019 Subscription Branch of PPP Patent, Uzhhorod, st. Project, 4