SU898360A1 - Method of group delay time non-uniformity meter checking and calibration - Google Patents

Description

one

The invention relates to radio measurements and can be used in testing and calibrating non-uniformity meters of group delay time (NGVZ meters) and group delay time meters (HRT meters).

Known methods of calibration and calibration of gauges NGVZ, consisting in the calibration and calibration of component nodes gauges NGVZ P

The disadvantages of these methods are that they do not provide for the verification and calibration of NGVZ meters as a whole and are laborious.

The known method of calibration and calibration of NGVZ meters is based on the measurement of known irregularities G2 by a measuring meter.

The disadvantages of this method are the greater labor-intensiveness of verification and calibration due to the necessity of alternately connecting the set of measures to the NGVZ; its implementation requires

a set of NGVZ measures designed for different fixed operating frequencies and different NGVZ to test or calibrate the NGVZ meter in the frequency range and the NGVZ range. The latter circumstance is explained by the fact that NGVZ measures, i.e., quadrupole networks with a known NGVZ value, are fundamentally inherent in the dependence of the TLV on frequency and they cannot be broadband.

The purpose of the invention is to reduce the labor intensity of verification and calibration.

This goal is achieved by the fact that the delay times vary synchronously with the change in the frequency of the output signal of the meter.

As a result, the NGVZ meter is affected by the group delay time manipulated synchronously with the manipulation of the frequency of the measuring signal, which is enough to simulate the NGVZ for the 38 NGVZ meter and perform verification and calibration. The method allows to use for testing and calibrating the NGVZ meters the quadrupoles possessing the null NGVZ and to construct a device for checking and calibration for the frequency band and a series of NGVZ nominal values. Example. An experiment was carried out to verify and calibrate the gauges for the gas turbine stack, for the NGBZ and for the attenuation of the LD-2 type HGF). The delay of the measuring signal is carried out by the delay line of analog signals of the LZS-100 type, the device with a charge-coupled device, which is made of B. The delay time is manipulated by manipulating the tracking frequency of the clock pulses, which are necessary to ensure the operability of the delay line. Clock pulses with frequency requirements are generated by a frequency synthesizer designed specifically for this purpose and providing a small discrete frequency tuning step. To manipulate the clock pulse frequency, synchronously manipulate the frequency of the output signal of the meter to the sync input (manipulation) of the synthesizer from the NGVZ meter, pulses are sent, which are shown in the meter E1N of the carrier frequency of the output signal (from the polar signal) signal. The meter opens up, since the impulses of the sync clock pulse in the meter subjected to calibration and calibration are not displayed on the cell. or connector. The device is controlled by controlling the frequency of the synthesizer clock. Practically all the GDT meters are based on the Nyquist method and the NGVZ meters based on the modified Nyquist method. Output measurement signal measure l NGVZ - this is a harmonic oscillation with. by a manipulated frequency and a continuously modulated amplitude. When manipulating the frequency of the measurement signal, two non-supportive frequencies f are set.

frequencies

V svippimayama (changeable) frequency

and

Claims (2)

The amplitude of the oscillations modulates C with a frequency Fj. The measuring signal after the passage of the investigated track-clock periods are synthesized on the basis of a quartz frequency of 10 MHz, i.e., oscillations with a period of 0.1 µs, which allows the discrete step to creep, is fed to the input of the meter. The measured NGVZ DTG is determined in the meter using the AT algorithm; -t: (- F x (f} - -, T; -t: Uo) -UCfc) - a-JTFM where T (o) and (fc) ™ 3 at frequencies f Q and f; e) (fp) and AHCic) phase shift difference when the frequency is changed by + Pd with respect to f and, respectively (Fig. I). If the device for calibration and calibration, turn on the transmitting and receiving parts of the NGVZ meter, has a linear phase-frequency characteristic (Fig. 1, curve 1), then THIS corresponds to a constant HRT and the NGVZ meter shows a zero NGVZ: D С 0. However, if manipulated the slope of the linear phase-frequency characteristic, i.e., manipulating the GDT synchronously with the manipulation of the frequency of the measuring signal of the meter (Fig. 1, curve 2), then for the NGVZ meter can be simulated; NGVZ, other than zero, in the frequency band. In the case of manipulation of the group delay on two levels (fig. 2 a), the constant NGVZ is obtained: LT 1 pk Sddr, n, where Г .. „-, is the maximum delay time or the delay group, the minimum delay time or the delay group (FIG. 2 b). DT can be changed by changing and / or Cm of the delay of the LZS-100, having 100 elements of 1x delay cells (SHO delay cycles), provides the values of NGVZ, which follow the formula LT-Cr-H. 100T, -100T TD. T, where T and V2, delay times; 4- durations of the periods of the following clock pulses, exposed during manipulation. Dannia are tabulated by the NGVZ in the 10th ISS with high accuracy. Results are monitored on indicators of a repeatable LD-2 meter having calibrators of its components. Switching the delay time to three levels by the law shown in FIG. 3a, the NGVZ DS is changed according to the law of the meander (Fig. 36). The span of the meander tn- (Tmax-Cmin C moxSmin) MCSKC-MW The switching rules for delaying a greater number of levels can also be used. The change in the NGVZ at the stake of the meander can be obtained the same by manipulating the GDT in two levels (Fig. 4 a, b). The calibration and calibration of the NGVZ meter is carried out by simulating a constant NGVZ or on the span of a meander of the GNVZ. Verification and calibration can be performed with the meter group metering with delay switching on and off. The use of the proposed reduces the complexity and. calibration, since for checking and calibrating all the NGVZ subbands of the meter at different frequencies, a single device is enough and there is no need to alternately connect a whole set of NGVZ measures. The method allows the construction of a device for verification and calibration with calculation for the operating frequency band and a series of NGVZ nominal values, in contrast to the NGVZ measures, which are calculated for fixed frequencies and NGVZ nominal values. Claims The method of calibration and calibration of non-uniformity meters for group delay is based on determining the known irregularities by a calibrated meter by delaying the output signal of the meter and then introducing a delayed signal into the meter, characterized in that, in order to reduce the labor-intensiveness of calibration and calibration, the delay time varies synchronously with the frequency change of the output signal of the meter. Sources of information taken into account in the examination 1. Journal of Communications, 1973, No. 12, p. 17-20. 2.Sb. Scientific instrument making and automation of scientific experiment, Krasnoyarsk, 1978, p. 27-36. Sh t Low frequency c fo fc fo fc fo fc fff fc four .i Fig 2 fff fc fff fc /; fa fc fa fc fo fc fo fc f, fc fo f f.