SU502370A1 - Calibration device for group time meters - Google Patents

Description

The invention relates to a phase-measuring technique, can be used mainly for calibration of group time delay meters (GDT), operating in the iB low frequency range.

A device is known for calibrating the group time deceleration meters, built on a dual variable capacitor, the rotor plates of which are driven into continuous rotation by an electric motor, and the stator plate of one of them is connected to a dividing head, with which the depletion time is counted.

However, in the known device, fluctuations of the phase of the amplitude-modulated (AM) voltage envelope arise due to instability of rotation of the electric motor, inconsistency of the gear ratio from the electric motor to the rotor of the variable capacitor plates, backlash in the sub-motors of the electric motor and the variable capacitor, etc.

In addition, in the prototype, its own reference voltage with a frequency equal to the frequency of the envelope is replaced by the reference voltage from the testing device itself, which leads to an incomplete calibration of the measuring starter. For example, p: in the verification of these: M device can not determine the error due to inequality and instability

frequencies of reference oscillators of the device being turned on and the meter itself.

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

The proposed device is equipped with a multi-valued measure of phase shift and a modulator connected between the output of the low-frequency filter and the input of the band-pass filter. In this case, the second input of the modulator is connected to

the output of the carrier oscillator, and a multi-valued measure of the phase shift is connected between the output of the reference frequency generator and the input of the filter with a frequency scan.

In order to eliminate the error due to the divergence of the frequencies of the generators of the frequency reference and the device being tested, the second input of a multi-valued measure of the phase shift is connected to the second input of the device under test.

The block diagram of the device shown in the drawing.

The device contains a series-connected reference frequency generator /, a multi-valued phase shift measure (MFSM)

2, a low frequency filter 3, a modulator 4, a lokose filter 5, an output device 6. To the second input of the modulator. The output of the carrier frequency generator 7 is connected.

The device works as follows.

Reference Generator Voltage

/ arrives at the multi-valued phase one move (MFSM) 2. Two voltages are removed from its outputs with a frequency that is different from the modulation frequency at which the rotatable device 5 operates, and with a known phase shift between them. with the help of a switch, the incoming B is the composition of the MFSM.

The voltage from the measurement output of the MFSM 2 is fed through a low-frequency filter 3 to the modulating -input of the modulator 4. The carrier voltage is applied to the Modulator from the carrier frequency generator 7.

The amplitude-modulated voltage from the modulator through the no-pass filter 5, which suppresses the modulation by-products, and the output device goes to the measuring input of the device to be verified.

Before starting the measurements, the output frequency of the MFSM 2 is set to the same frequency, the frequency of which the reference channel operates according to (the true gauge of the group-side deceleration time).

Using the switch included in the MFSM 2, set the phase shift between the reference measuring output of the MFMS equal to zero and transforms the device under test into the synchronization mode (zero setting) on the measuring signal at the input. After synchronization of the device being turned, its device translates to the measurement mode and, given a shift, at the measuring output of the MFSM. compare the readings of the MFSM readout device and the device to be checked.

In this version of the test, the device under test synchronized its reference voltage by the envelope voltage of the AM signal at its input, i.e., the measurement voltage of the device itself, previously synchronized with respect to the input voltage, is used for measurements.

In the event that such a verification mode is unacceptable for a scanned instrument due to its structural construction, and in the case when it is necessary to eliminate the error due to the divergence of the frequencies of the reference oscillators of the scanned device to the verification instrument, to the reference input of the scanned instrument 8 connect the output from the reference channel MMFS, and the phase difference between the reference and measuring channels MMFS in units of time is compared with the readings of the instrument being tested.

For the calibration of the error of the device being checked, due to the inequality of the frequencies of the reference generators, it is necessary, after synchronization of the device being tested, to transfer it to the measurement mode, and from its readings in the interval wounded by time measured and with the device under test in one measurement cycle, one can estimate the value of errors. The instability of the frequency of the reference frequency generator must be equal to the instability of the frequency of the reference oscillator of the device being tested, or better than e: e, and their frequencies are equal and / 1 and are multiples of each other.

5 In the proposed device, the electric motor and all other nodes that cause the fluctuation of the AM voltage envelope phase are excluded. The newly introduced blocks do not introduce phase fluctuations and allow for this.

0 increases the accuracy of the readout of the installation to be installed and greatly simplifies the circuit of the device, making it possible to build it over a single channel.

The use of a multi-valued measure of phase shift 3 combined with the corresponding inclusion of the remaining nodes of the device allows for higher accuracy of calibration, determined mainly only by the speed of 0. we will be included in their composition of recalculating circuits or ring counters.

Claims (1)

Invention Formula 5 A verification device for group spin and delay meters comprising a carrier frequency generator and a reference frequency generator, a low frequency filter and a series-connected band-pass filter and an output device to which a rotatable device is connected, characterized in that, in order to improve the verification accuracy, it is equipped with a multi-valued phase shift measure and a modulator connected between 4.5 output of the low-frequency filter and the input of the band-pass filter, while the second .input module is connected to the output of the carrier frequency generator, and a multi-valued phase shift measure is connected between the output of the reference frequency generator and the input of the low-frequency filter.