SU375578A1 - DEVICE FOR MEASURING SHIFT PHASE AND WEAKNESS OF FOUR-POLES - Google Patents

Description

I

The invention relates to the field of radio metering technology and (May be used to simultaneously measure two parameters: phase shift and attenuation.

There are known devices for measuring phase shift and attenuation of quadrupoles, which contain a power generator connected to a directional coupler forming a bridge branch, one of the channels of which contains series-connected phase shifter and attenuator, the other of the quadripole under study, and the output signals of both channels are fed through directional couplers through a mixer on the oscillographic indicator.

The purpose of the invention is to obtain simultaneous information on the oscilloscope screen about the deviation of the measured shift and attenuation values from the nominal value.

The goal is achieved by introducing a phase and two amplitude electrically controlled modulators into the device, with one of the amplitude modulators connected between the power generator and the directional coupler forming the branching of the bridge, and the series-connected phase and second amplitude controlled modulators are connected between directional coupler, forming a fork of the bridge, and the measured quadrupole.

FIG. 1 is a block diagram of a device for measuring phase shift and attenuation of quadrupoles; in fig. 2 shows diagrams of his work (a - phase change,

b - power at the output of the amplitude modulator; c is the power at the inlet of the branch; in fig. 3 shows the image on the oscilloscope screen.

Power generator 1 is connected via

an electrically controlled amplitude modulator 2 with a directional coupler 3 dividing the power flow into two channels. In one of the channels, a phase shifter 4 and an attenuator 5 are installed. In the other channel, there are electrically controlled phase modulator 6, electrically controlled amplitude modulator 7 and four-pole measured 8. The channels are transmitted through the directional couplers 9 and 10 to the mixer 11 and then to the oscilloscope 12. The amplitude modulator 7 is connected at a low frequency with an audio frequency generator 13. The amplitude modulator 2, the phase modulator 6 and the oscilloscope 12 are connected

with low-frequency unit 14. The free ends of the directional couplers 3, 9 and W are loaded on the agreed load 15-19. The phase modulator 6 performs frequency shifting and measurement transfer

frequency The magnitude of the phase modulation is set equal to the maximum permissible deviation of the measured phase shift from the nominal ± phax (Fig. 2a). The amplitude modulator 7 (FIG. 26) performs multiple modulation of the phase-shift signal, which is achieved by supplying the modulator from the sound generator-generator 13 with a frequency far exceeding the frequency of the phase adjustment by the phase modulator 6. permissible deviation of the measured attenuation from the nominal (dB). The amplitude modulator 2 (Fig. 20) forms the boundaries of the portion within which the permissible phase deviations from the nominal are established. This is achieved by the fact that the modulation frequency of the amplitude modulator 2 is synchronous and similar to the frequency of adjustment of the phase modulator 5 and equal to the frequency of the sweep of the oscilloscope 12.

The device works as follows.

From FIG. 2a and 26 it can be seen that in a very short time, A During which the phase of the signal remains almost unchanged, the amplitude of the signal undergoes a multiple change within AL. This condition is fundamental and allows solving the problem of simultaneously measuring two parameters: phase shift and attenuation.

The measurement is carried out as follows. The device is compensated for zero with a phase shifter 4 and an attenuator 5. Next, the phase shifter 4 and the attenuator 5 are set to the nominal phase shift and attenuation values for the measured quadrupole. Then, the required modulation level of the electrically controlled modulators is entered. The evaluation of the measurement results is performed on the oscilloscope image shown in FIG. 3. Results are evaluated by the position of the points A t B relative to the rectangle VGDE. The measured quadrupole is considered suitable if point A is located on the straight line BE, and point B does not extend beyond the boundaries of the VGDE rectangle.

Subject invention

A device for measuring the phase shift and attenuation of quadrupoles, containing a power generator connected to a pickled coupler, forming a bridge junction, one of the channels of which contains series-connected phase shifter and attenuator, the other one of the quadrupole under study, and the output signals of both channels are fed through directional taps through the mixer to oscillographic indicator, characterized in that, in order to obtain simultaneous information on the screen of the oscillograph on the deviation of measured shift and attenuation from nominal, phase and two amplitude electrically controlled modulators are introduced into it, with one of the amplitude modulators connected between the power generator and the directional coupler forming the branching of the bridge, and subsequently connected phase and second amplitude controlled moduli The tori are connected between the directional coupler, which forms the branching of the bridge, and the measured quadrupole.

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