SU1061079A1 - Method and device for measuring alternate magnetic field induction - Google Patents

Abstract

1. A method of measuring the induction of an alternating magnetic field, consisting in the influence of a measurable magnetic field on a magnetometric converter, through which a direct current passes, emissions of a variable component of the output signal of the converter, and measuring it, in order to extend the measuring range, the selected variable component of the output signal of the converter is summed up with the additional constant signal until the duration of the polo is equal and negative flax Q half cycles of the sum signal, S and the measurement is carried out on a linear (A half cycle measuring transducer characteristics. of sl with

Description

2, A device for measuring the induction of an alternating magnetic field containing a series-connected direct current generator, a magnetometric converter / capacitor, and a recording unit, characterized in that, in order to extend the measurement range, a controlled positive pulse generator is additionally added to it the first amplitude of the pulses, the adder of the effective values of the pulse signals and the controlled DC voltage generator The second one is connected to the second input of the registration unit, as well as sequentially connected controlled pulse shaper of negative polarity and the second limiter of pulse amplitudes, the gain of which is connected to the second input of the adder of the effective values of the pulse signals, and the positive and negative effects of the pulse formers Polarities are connected to the first input of the registration unit.

This invention relates to magnetic measurements and is intended to measure alternating magnetic fields.

The known method of measuring the induction of an alternating magnetic field is by placing two Hall sensors in the measured field, passing a direct current through the first one, and passing through the second an alternating current from the Hall EMF of the first sensor and selectively measuring the voltage at the Hall contacts of the second Hall sensor.

A device for implementing this method contains a DC generator, a Hall sensor connected to it, the Hall contacts of which are connected to the current contacts of the second Hall sensor, and a selective voltage meter connected to the Holo output KjoHTaKTaM of the second Hall sensor l

However, the known method and device for its implementation provide a nonlinear dependence of the measured voltage on the amplitude of induction of an alternating magnetic field (quadratic), which, given the low sensitivity of the Hall sensors, leads to a limited dynamic range of measurements.

The closest to the proposed technical essence is the method of measuring the induction of an alternating magnetic field, which consists in influencing the measured magnetic field on a magnetometric transducer through which direct current passes, isolating the parchment component of the output signal of the transducer and measuring it.

A device for implementing an inoi-inofo stazoba contains a series-connected direct current generator, a magnetometric converter, a capacitor, and a recording unit 2.

However, the known method and device for its implementation does not provide a linear measurement of induction, which is associated with the specified specifics; transducer characteristic and

. limits the use of the method in teslameters with wide measuring limits

The purpose of the invention is to expand the measurement range.

The goal is achieved by the fact that, according to the method of measuring the induction of an alternating magnetic field, consisting in the action of the measured magnetic field on

a magnetometer converter, through which a direct current is passed, extracting a variable component of the output signal of the converter and measuring it, a selected variable component of the output signal of the converter sums with an additional constant signal until the equality of the duration of the positive signal is equal

and negative results of the total signals, and measurements are made on the linear half-period of the measuring characteristic of the converter.

The proposed method is implemented

a device for measuring the induction of an alternating magnetic field containing a series-connected constant-current generator, a magnetometric converter, a capacitor and a recording unit, into which the series-connected controlled positive pulse driver, the first pulse amplitude limiter, the adder of the effective values of the pulse, controlled signals, a constant voltage generator, the output of which is adventurous to the second input of the registration unit, and that the series-connected controllable driver pulses of negative polarity and a second pulse amplitude limiter, vyhodch otorrhea connected to the second input of the adder nmpulsnyh effective values of the signals, and inputs a control pulse shaping e Mykh positive and negative half rnoetey connected to first register entry block. Figure 1 shows the block diagram. Device for the implementation of the proposed method; 2 shows timing diagrams for the operation of the device. A device for implementing the method comprises a series-connected DC generator 1, a magnetometric converter 2, a capacitor 3 and a registration unit 4 of a series-connected controlled driver 5 pulses of positive polarity, a first OG limiter 6 pulse amplitudes, an adder 7 of effective values of pulse signals and a control A constant voltage generator 8, the output of which is connected to the second input of the registration unit 4, as well as a serially connected control driver 9 imp. sov of negative polarity and a second pulse 10 confine nichitel amplitudes you turn is connected to the second input of the adder 7, the effective values of the pulse signals, and inputs actuated formers 5 and 9 and the positive pulses. negative polarity is connected to the first input of block 4 of registration. The method is implemented as follows. When passing through a transform. a 2-DC generator from a generator 1 and an alternating field with induction B B Bos; n (wib where BQ is the induction amplitude; U is the cyclic frequency; t is the time (Fig. 2a), on the converter, except for the constant voltage U (j from generator 1, a periodic information signal iU (Bg, t) arises, the frequency spectrum of which in the general case consists of a constant component voltage UQ and a number of harmonics. The total voltage on the converter 2 can be expressed by the following pattern:, U - Uo & UttiUoVZjbU 5in ((nulV + (.), de iU --- voltage, slowly changes to due to the amplitude drift of the output impedance of converter 2, independent of BO (this voltage compared to iiU (Boft) can be considered, quasi-constant); & IJQ, 0 - amplitude 1 of the harmonics of the information signal bU ( Bo, l); h is the number of harmonics. The time diagram of the voltage U (Bj ,, t) for one period for a typical galvanic combinator converter is shown in Fig. 26. Due to the linearity of the positive branch of the transfer characteristic during the positive half period, the time dependence iU (BQ, t) is sinusoidal mu law iUlBo.tbll-tJo-bUt eoSitiiwll, (3) where K is - proportionality factor. At the same time, the duration of the positive and negative half periods T | and T are equal to each other t, t. After passing the information signal through the capacitor 3 in order to prevent penetration into the measurement path of the constant voltage UQ and the quasi-constant bU, the value of the alternating voltage is uUcai) ((ui1l. all the constant components, including the i value. Due to the absence of the latter, the half-periods T and T are not equal to each other (Fig. 2b), (6) and for the voltage amplitude in the positive half-period (T), the ratio (3) invalid. To restore it, part of the information signal after condenser 3 enters shaper 5 and 9 pulses, in which it forms positive and negative polarity pulses with durations m} and T, respectively, and with repetition frequency fn (j / 2i). Limiters 6 and 10 maintain the same absolute values amplitudes of these pulses. The pulses thus obtained (pHr.2f) enter the adder 7 of the effective values of the pulse signals, the output voltage of which is proportional to

u, "Aj, u jt4K--: n)

about

where bU, is the pulse amplitude

(figg);

T And

-period;

- permanently. The voltage 11 is then supplied to the control input of the DC voltage generator 8, the transmission coefficient of which satisfies the coupling 61/0

iG (8) Subject to the relation (8) at the output of the generator 8 there is a constant voltage

Un uUo ,. (9)

where the timing diagram of the information signal at the input of block 4 of the registration is identical to that shown in FIG. 26, i.e. in the positive half-time, the relation (3) is valid. Performing the full-wave recording unit 4 provides a measurement of the amplitude or effective value of the voltage 4U (B (j, t)) in the positive half-period and, consequently, a linear induction conversion of the measured alternating magnetic field takes place.

Thus, when using the proposed method, in comparison with the known dynamic and linear ranges, the measurements are extended no less than three times. In addition, the proposed method extends the applicability of

0 magnetic measuring equipment of a large class of highly sensitive semiconductor converters characterized by only one linear branch of the transfer characteristic: magnetic diodes, magnetotransistors, etc. -.

Claims (2)

METHOD FOR MEASURING VARIABLE MAGNETIC FIELD INDUCTION AND DEVICE FOR ITS IMPLEMENTATION. (57) 1. A method of measuring the induction of an alternating magnetic field, which consists in the action of a measured magnetic field on a magnetometric transducer through which a direct current is passed, isolating the variable component of the output signal from the transducer and measuring it, which is different from expanding the measurement range, the selected variable component of the converter output signal is added up with an additional constant signal until the equality of the duration of the positive and negative HO- _with half cycles of the total signal, and $ measurement is performed on the linear half cycle measuring transducer characteristics'. SU,. ,, 1061079 2. A device for measuring the induction of an alternating magnetic field, comprising a dc generator, a magnetometer transducer, a capacitor and a recording unit connected in series, characterized in that, in order to expand the measurement range, it is additionally connected with a controlled pulse shaper of positive polarity, a first limiter pulse amplitudes, an adder of the effective values of the pulse signals and a controlled constant voltage generator, the output of which connected to the second input of the recording unit, as well as a serially connected controlled pulse shaper of negative polarity and a second pulse amplitude limiter, the output of which is connected to the second input of the adder of the effective values of the pulse signals, and the inputs of the controlled pulse shapers of positive and ^ negative polarity are connected to the first input of the registration unit.