SU1613981A1 - Method of measuring intensity of pulsed electric and magnetic fields - Google Patents

Abstract

The invention relates to a pulse technique. The goal is to improve the accuracy of measuring the electric or magnetic component of pulsed electromagnetic fields by expanding the dynamic range and reducing nonlinear distortions introduced into the measurement results. The measurement method is implemented as follows. Band-shaped frequency components are separated from the electrical signals, a control signal is formed proportional to the sum of the signals of the obtained band frequency components, and two correction signals are formed, each of which is proportional to the sum of the control signal and the corresponding low-frequency spectral components selected, and the correction signals are inverted and summed with a constant reference voltage, the received signals are amplified, folded with a corresponding constant reference voltage, and the proportion tional to the thus obtained signal is varied corresponding to the transform coefficient information of the light fluxes in the electrical signals. An increase in the correction signal causes a decrease in the corresponding conversion coefficient and vice versa. 1 il.

Description

The invention relates to a pulse technique and is intended to measure pulsed electrical or / and magnetic fields, and can be used in scientific research, in the operation of electrophysical and power plants.

The purpose of the invention is to improve the accuracy of measuring the electric and / or magnetic component of pulsed electromagnetic fields by widening the dynamic range and reducing the nonlinear distortions introduced into the measurement results.

 The essence of the method is that a polarized luminous flux is passed through a sensitive element, the luminous flux obtained thereafter is converted into two paraphase-modulated luminous flux, both streams are converted into output electrical information signals from which

with

QD 00

Corresponding low-frequency spectral components, up to frequency

-fnch

of the mentioned information

electrical signals have bandwidth components, lower

npc

and top f

vps

whose frequencies

are determined by the ratio

Fntz ips Hun

where fu .. „- lower limit frequency

PP

the spectrum of the measured components of the pulsed fields;

„- upper limit noise frequency

  noise spectrum,

form the control signal, directly supporting the sum of signals received by the bandpass frequency components, and form two correction signals: each of which is proportional to the sum of the control signal and the selected corresponding low-frequency spectral components, the correction signals are inverted and summed with a constant reference signal voltage, the received signals are amplified, they are inserted with a corresponding constant voltage reference voltage and received, so that the signal changes the corresponding coefficient converting light fluxes to informational electrical signals, with an increase in the correction signal caused by a decrease in the corresponding conversion factor and vice versa.

The drawing shows a block diagram of a device that implements this method of measurement.

A device that implements the method contains a flat-polarized i light source 1, the light from which enters the sensitive optical active element 2 and is analyzed by a two-beam reproducible analyzer 3, the light rays from which enter the avalanche photodetectors 4 and 5, the outputs of which are connected to the output pins of the device and are connected via .band filters 6 and 7 to the input of the first summing unit 8, and through low-pass filters 9 and 10 to the first inputs of the second and third summing blocks 11 and 12, respectively, the second inputs otorrhea vyhodu.tservogo connected to the summing block 8 outputs of said summing units 11 and 12 are connected to the inputs you 0

five

0

five

0

five

0

45

50

55

readable reading blocks 13 and 14, to the inputs of which to be reduced — a source of constant reference voltage is connected. The magnitude of this voltage is equal to the common-mode voltage at the outputs of the avalanche photodetectors 4 and .5, The output voltages of the reading blocks 13 and 14 are amplified operational amplifiers 15 and 16, the outputs of which are connected to the first inputs of the fourth and fifth summing blocks 17 and 18, to the second inputs of which are connected the corresponding sources of the constant reference voltage Ujj and oii. voltages are selected individually for each particular avalanche photodetector instance in order to ensure the same conversion coefficient of the various photoelectric detectors. The outputs of the fourth and fifth summing blocks 17 and 18 are connected to the inputs of the control of the conversion coefficient. nor (power) avalanche photodetectors kov 4 and 5.

The device works as follows.

If the two-beam analyzer 3 is rotated in such a way that, in the absence of the field to be measured, the plane of polarization of the incident light is symmetrically relative to the planes of the orthogonally polarized components of the transmitted light and the optical active element 2 is impulsed by an electric (magnetic) field The components of light transmitted through analyzer 3 contain: two components of the first component do not depend on the intensity of the measured field and rational of the total optical power transmitted through the device. The second component is proportional to the product of the total optical power and the sine of the angle resulting from the rotation of the polarization plane proportional to the intensity of the measured field. If the rotation angle does not exceed if / 10, the second component can be considered proportional to the product of the total optical power transmitted through the device for example, the sensitivity of the measured field, TaicHM, low-frequency fluctuations of the total

five

The optical power is supplied by a source of multiplicative and additive interference simultaneously, the spectrum of which is concentrated in the frequency band of about Hz - 100 kGi.

The signals at the outputs of photodetectors 4 and 5 also have two components, the first one is in-phase, proportional to the total optical power, and the second is paraphase, and is proportional to the total optical power to the measured field strength. To perform the in-phase component, the first summing unit is used. When measuring the parameters of pulsed electromagnetic fields, when the spectra of the technological noise of the light source and the measured pop partially overlap, it is necessary to limit the input signal bandwidth to increase the accuracy of the noise components in the summing unit 8. This is achieved by applying bandpass filters 6 and 7, the bandwidth of which must be somewhat wider than the frequency range from fu to fa. Output signal

Hrs

the low frequency filters U and lU with the upper limit frequency equal to the lower limit frequency of the band filters 6 and 7 contain only those spectral components of the technological noise and mechanical vibrations that do not overlap with the spectrum of the measured fields. Sum with the output of the first summing block. 8 and entering the inverting inputs of the subtracting units 13 and 14, these signals are subtracted from the reference voltage Ugi-, which leads to a decrease in the error signal at the outputs of the operational amplifiers 15 and 16 "The sum of the reference voltages Uong of the corresponding error signals is the supply voltage avalanche photodetectors 4 and -5.

For avalanche photodetectors, the individual dependence of the conversion factor S on the individual factor is strongly dependent on many external destabilizing factors (temperature, spatial beam shifts, optical aging, etc.).

Depends on supply voltage

and „, (3)

 Pete

S

,; 7i:

981

where S is the coefficients conversion,

without avalanche multiplication; and - avalanche voltage; p - technological coefficient

n 1 ... .3 o

Consequently, as the supply voltage decreases, the avalanche photodetector conversion factor decreases, followed by a decrease, the output voltage of the photodetectors increases and the error signal increases, the supply voltage rises again, and the output voltages of the photodetectors recover.

Claims (1)

Invention Formula 0 Method of measuring stress pulsed electric and magnetic fields, which means that the polarized light flux is converted into two paraphase-modulated light flux, both fluxes are converted into electrical output signals, from which the corresponding low frequency spectral components, i.e. characterized by the fact that, in order to improve the accuracy, of the electrical signals, band frequencies are compiled, form a control signal, proportional to the sum of the signals of the received band frequencies s constituents and form two corrective br, their signal kazhdyGt of which is proportional to the sum of the control-fulvus Nala and 40 g vdelennyh corresponding low-frequency spectral components, correction signals are inverted and summed with a constant reference voltage ,. The received 45 signals are amplified, added to the corresponding constant reference voltage, and in proportion to the signal obtained in this way, the corresponding coefficient of conversion of light fluxes into information electrical signals is changed, and an increase in the correction signal causes a decrease in the corresponding conversion coefficient, and vice versa. The „5 5 and upper fgnc frequencies are determined by the relation (.. UST iwsh willows.1