SU1352380A1 - Magnetooptic meter of current periodic pulse parameters - Google Patents

Abstract

The invention can be used to register the shape of periodic current pulses to measure their amplitude and to improve the measurement accuracy. In a magnetic field, there is a Farad cell, optically connected through a polarizer 2 to a source 3 of light and through an analyzer 4 to a photoreceiver 5 connected to a preamplifier 6. A rectifier 7, a two-coordinate recorder 8, waiting for multivibrators 9, 13 and 14 are inserted into the device generators 10 and 12 of the sawtooth and slowly increasing voltage and power amplifier 15. Due to this, the signal is amplified by the preamplifier 6, which is tuned to a frequency N times the pulse frequency of the measured current. As a result, the measurement error is reduced due to the noise of the light source 3 and the photodetector 5. 2 Il. ABOUT

Description

The invention relates to electrical measuring equipment, in particular, to magneto-optical current meters, which are based on the Farad effect, and can be used to record the shape of periodic current pulses and measure their amplitude.

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

FIG. 1 shows a structural diagram of a magneto-optical meter; in fig. 2 is a diagram of his work.

The meter contains a Farada cell 1 located in the magnetic field of the measured current, optically connected through a polarizer 2 to a source 3 of light and through an analyzer 4 to a photo-receiver 5 connected to a narrow-band preamplifier 6, which is connected via a rectifier 7 to the Y input two-coordinate register 8, the synchronization input of the magneto-optical meter through the first waiting multivibrator 9 and the generator 10 of the sawtooth voltage, is connected to the first input of the comparator 11, the second input of which is connected to the first generator 12 of a slowly increasing voltage and X input of the two-coordinate recorder 8, and the output of the comparator 11 with the inputs of the second 13 and third 14 waiting multivibrators. The output of the second idle (its multivibrator 13 is connected to the second input of the third waiting multivibrator 14, the output of which is connected to the light source 3 through the amplifier 15.

 The device works as follows.

For the input clock pulse U (5 (Fig. 2a), which is ahead of the measured current pulse i (Fig. 26), the first waiting multivibrator 9 generates a rectangular pulse and (Fig. 2c) with a duration exceeding the maximum possible

ten

15

20

voltage U and generates pulses Up (Fig. 2e), the fronts of which coincide in time with the moments of equality of the voltages at the inputs of the comparator 11, On the front edges of these pulses, the second pending multivibrator 13 generates pulses Uj (Fig. 2g), the duration of which is pre - the maximum possible pulse duration of the measured current will be exceeded. The third standby multivibrator 14 generates short pulses Uj (Fig. 2i), coinciding with the front and rear edges of the output pulses of the second standby multivibrator 13, these pulses through the power amplifier 15 control the source of light 3. Thus, the light source generates a pair of light pulses, the first of which coincides with one of the instantaneous values of the measured current, and the second is formed after the end of the current pulse. As 2 changes the output voltage of the generator. 12 slowly increasing voltage, the delay of the pulses emitted by the light source 3 relative to the synchronizing pulses changes from zero to a maximum, and the first of the light pulses alternately coincides with all the instantaneous values of the pulses of the measured current. The pulsed luminous flux of the light source 3 passes the polarizer 2 and falls on

35 cell 1 Farad located in the magnetic field of the measured current.

The azimuth of polarization of the first light pulse after cell 1 Farad is changed by the angle, proportional

40 to the instantaneous value of the measured current at the moment of action of this pulse, and the polarization azimuth of the second pulse does not change. After analyzer 4, the changes in azimuth are converted to

45 changes in the intensity of the light flux, which the photodetector 5 converts to an electrical signal U f (Fig. 2k). From this signal, narrow-band amplifier 6 emits the K-th speaker

thirty

the duration of the pulse measured by a mono is the frequency of the successor. The sawtooth voltage generator 10 generates a sawtooth voltage, the duration of the linear part of which Un (Fig. 2d) slightly exceeds the possible pulse duration of the measured current. The comparator 11 compares the output voltage Uj (Fig. 2e) of the generator 12 of slowly increasing voltage with the sawtooth

five

0

voltage U and generates pulses Up (Fig. 2e), the fronts of which coincide in time with the moments of equality of the voltages at the inputs of the comparator 11, On the front edges of these pulses, the second pending multivibrator 13 generates pulses Uj (Fig. 2g), the duration of which is pre - the maximum possible pulse duration of the measured current will be exceeded. The third standby multivibrator 14 generates short pulses Uj (Fig. 2i), coinciding with the front and rear edges of the output pulses of the second standby multivibrator 13, these pulses through the power amplifier 15 control the source of light 3. Thus, the light source generates a pair of light pulses, the first of which coincides with one of the instantaneous values of the measured current, and the second is formed after the end of the current pulse. As the output voltage of the generator changes. 12 slowly increasing voltage, the delay of the pulses emitted by the light source 3 relative to the synchronizing pulses changes from zero to a maximum, and the first of the light pulses alternately coincides with all the instantaneous values of the pulses of the measured current. The pulsed luminous flux of the light source 3 passes the polarizer 2 and falls on

5 Cell 1 Farad located in the magnetic field of the measured current.

The azimuth of polarization of the first light pulse after cell 1 Farad is changed by the angle, proportional

0 to the instantaneous value of the measured current at the moment of action of this pulse, and the azimuth of polarization of the second pulse does not change. After analyzer 4, the changes in azimuth are converted to

5 changes the intensity of the light flux, which the photodetector 5 converts to an electrical signal U f (Fig. 2k). From this signal, narrow-band amplifier 6 emits the K-th speaker

0

no pulses, amplifies it, and rectifier 7 detects. The output voltage of the rectifier 7, proportional to the instantaneous value of the measured current at the time of the first light pulse, is applied to the Y input of the two-coordinate recorder 8, the X input of which receives the voltage from the output of the generator 12

slowly increasing voltage, proportional to the delay of the first light pulse relative to the synchronization pulse.

Thus, the odds on the pulse of the measured current is recorded on the two-coordinate recorder. To ensure the normal operation of the meter, it is necessary to perform a ratio

.. 2t + 1 2Nf

where t- is the delay between first and

second light pulses;

f is the pulse frequency; N is the harmonic number that

distinguished by a narrowband amplifier, n e N.

Claims (1)

Thus, the signal is amplified by a narrow-band amplifier tuned to a frequency that is N times as large as the pulse frequency of the measured current. As a result, the measurement error due to the noise of the light source and the photodetector is reduced, and consequently, the measurement accuracy is increased. Invention Formula A magneto-optical meter of periodic current pulse parameters, containing a Farad cell, located in the magnetic field of the measured current, optically coupled through a polarizer with a light source and through an analyzer — with a photoelectric device connected to a preamplifier; , in order to increase the measurement accuracy, it is additionally equipped with three waiters, multivibrators, a sawtooth generator, a slowly increasing n-apr generator, a comparator, g with a rectifier, a power amplifier and a two-coordinate recorder, while the pre-amplifier is narrowband and connected through a rectifier to the Y-input of a two-coordinate recorder, the synchronization input of the magneto-optical meter through the first waiting multivibrator and the sawtooth voltage generator is connected to the first input of the comparator, g the second input of the comparator is connected to the output of a slowly increasing voltage generator and the X-input of the two-coordinate recorder, and the output of the comparator is connected to the inputs of the second and third standby multivibrators, the output of the second standby multi-; vibrator is connected to the second input of the third standby multivibrator, the output of which through the power amplifier connected to a light source. 0 V j j j j j FI.2