SU1215051A1 - Method of determining group time lag - Google Patents

Description

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FIELD OF THE INVENTION The invention relates to a revdio technique and can be used. Used when measuring the parameters of the reciprocal devices.

The purpose of the invention is to improve the measurement accuracy.

The goal is achieved by the fact that at the frequencies F, and Fg create interference of the waves in the sensors} the phase shift between the sensor signals is determined; simultaneously delaying the mutual signals; create interference between delayed and non-delayed signals; determine the phase shift between the sensor signals.

The drawing shows a block diagram of a device that implements a method for measuring group time} 1and delay.

The device that implements the proposed method consists of the object under study 1, connected to the measuring sections 2 and 3 of the microwave generators 4 and 5, synchronized by the reference generator 6, the meters 7 and 8 of the amplitude ratios of the signals, which are synchronized by the reference generator 6 and the computer 9 for processing measurement results.

The device circuit can be implemented using serial devices. The reference generator 6 can be any frequency standard or frequency synthesizer. The microwave generators 4 and 5 are serial oscillators, the input on the FALCH. As the measuring sections 2 and 3 you can use the measuring line. Measuring sections - measuring devices 2 and 3 of amplitude relations consist of voltmeters and key devices.

A method for measuring latency latency is as follows.

The frequencies of oscillators 4 and 5 are coherent and offset. The signals supplied directly to the measuring sections 2 and 3 are reference, and the same signals passed through the measured quadrupole and received in section 3 and 2 are measuring, since their modules and phases change in accordance with the transmission coefficient measured device. The reference and measurement signals create an interference pattern in the measurement sections 2 and 3. The standing waves resulting from the interference,

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The CEC of coherent signals is continuously shifted with respect to the planes of communication lines in the sensors. Measuring 7 and 8 amplitude ratios

The amplitudes of the standing waves are measured at the instants of time when the clock pulses arrive from the reference generator 6. The number of measured values of the standing wave amplitudes

Its period, equal to the period of the difference frequency of the signals of the generators 4 and 5, is determined by the requirements of the measurement accuracy and the technical possibilities of the implemented measurement circuit. Thus, through the ratio of the measured values of the amplitudes of the standing wave, the phases of the transmission coefficients are determined from both sides. Before switching on the object under study 1, the measuring system is calibrated and the measured values of the phases are stored in the computer 9. After turning on the measuring device again

5, phase values are determined. In this case, the phases of the transmission coefficients are determined simultaneously at two frequencies F, and Fjj. Time group latency is determined by the ratio

. phase differences to the difference of the angular frequencies of the oscillators 4 and 5. For example, the complex signals from oscillator 4, 1 st,, from oscillator 5 after passing through the device under study vary in magnitude and phase, see, receive. type and where JK, K, and, are the complex transmission coefficients at the frequencies of the input and output of the probe0

W, and W

 my devices: the sum of pairs sigg y, "e4 K, y ,, and and.

GG 1G (B r ftfiao l T f pf aistxa -at

signals

Thu 2, form standing waves.

displaced relative to the plane of the communication probes with an angular frequency and W, - (Hf. Amplitude ratio meter 7 measures the signal whose phase is proportional to the transmission coefficient at frequency Q, the amplitude ratio meter 8 measures the signal whose phase is proportional to the transmission coefficient at the frequency Thus, by making a series of calibration measurements without a quadrupole under study and a measurement with a quadripole under study, it is possible to determine the phase shifts at frequencies O) and Mj produced by the device under study. . The frequency difference can be adjusted to within fractions of Hz. Confirm the accuracy of the measurement accuracy. When measuring the phase of the points in the measurement result

measurement errors are caused by a change in the geometric dimensions of flexible coaxial cables or waveguides. The errors that arise in this case refer to additional errors due to mismatch, which increase with an increase in the frequency of the group delay time ostaty. The reflection coefficients of flexible waveguides on the side of the device under study are determined by the known ratio

s. gr

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The phase shift between the reference and measurement signals, while simultaneously detaining the signals at the frequencies Fj and F, 15, creates an interference between the delayed and reference (non-delaying) hinges, improves the measurement accuracy by reducing the measurement time and eliminating the reflection error of the connector. - 20 measurements due to the bend of the flexible waveguide; flexible waveguide path. The frequency range has no practical limit. The systematic characteristics of the microwave measuring sections 25 can be excluded from the result of measurements by special calibration.

where S (, ejj is the complex coefficient — the complex transmission coefficient of the flexible waveguide; Gr is the complex reflection coefficient of the measuring sections.

When a flexible waveguide is bent, the modulus and phase of the transfer coefficient 3,. For example, at., 5 ° for each flexible waveguide, and there are two of them, with the method being measured by {1 pointwise, this error with the most unfavorable variant can accumulate and amount to cf, ,, ,, ,, 1, (taking into account calibrations and measurements) .

In the proposed method, this error is not included in the result of measurement.

Claims (1)

Invention Formula 30 A method for determining the group delay time, based on measuring the phase shift of a mezvdu support and measuring 4 signals, which is due to the fact that, in order to improve the measurement accuracy, signals at frequencies F and Fg are simultaneously delayed, creating interference between the delayed and reference (non-delayed) signals and measure the increment of the phase shift between the signals at frequencies Fj- and F, and the time of the group eap 1 sdation is determined by the formula since frequency f, And F ottireny, between themselves no more than 100 Hz and, therefore, phase distortion at frequencies F, and P can be considered the same. When determining the state of emergency 4, lW, HAt | ,,  g Q, -CJj tf. (tJ.) - CfJCJ,) M.-CJ, I And phase distortions are mutually exclusive. Standard measuring instruments, measured at x, have their own zero drift, which VNIIPI Order 903/53 Circulation 730. Subscription Branch ShSh Patent, Uzhgorod, ul. Project, 4 15051 during long-term measurements, it is included as an error in the measurement result. But since time is shortened due to the reduction of measuring operations, 5 therefore, the measurement error caused by the temporary instability of the measuring devices is reduced. From this it follows that measurement five Invention Formula 0 The method of determining the group delay time, based on measuring the phase shift of a mezvudu support and measuring 4 signals, which is due to the fact that, in order to improve measurement accuracy, the signals at frequencies F and Fg are simultaneously delayed, creating interference between the delayed and reference (non-delayed) signals and measure the increment of the phase shift between the signals at frequencies Fj- and F, and the time of the group eap 1 sdation is determined by the formula , 1СыЛ- Ctdгl where t is the group delay time of the signal; C |, Chg phase shifts between Q. signals; Wj.ujj is the circular frequency of the first and second signals at frequencies F, and F. 0