SU834633A1 - Proton magnetometer - Google Patents

Description

(54) PROTON MAGNETOMETER

I

The invention relates to magnetic measurements and is intended to study the weakly magnetic anomalies of the Earth's magnetic field, within (0,) 10 n T.

A proton magnetometer is known, consisting of a sensor with a liquid, a polarization coil, a reading coil, a polarization energy source, a switching polarization circuit, an amplifier, a band-pass filter, a limiter, a differentiating circuit, a multiplier, a phase shifter, an AND circuit, a trigger, and a control circuit counter 1.

A disadvantage of the known device is the inability to synchronize the inclusion of the frequency multiplier at the right time with the precession signal.

The YMP-3 proton magnetometer is known, consisting of a sensor, a limiting amplifier, a polarization current driver, a counter, a control circuit, a frequency multiplier containing a phase detector, a switch, an H4 filter, a voltage controlled oscillator, a frequency divider and a manual circuit. multiplier adjustments that allow the multiplier to be adjusted to the center of the band J ae | lzhani 2.

The main disadvantage of the known magneto-meura is the lack of reliable synchronization of the moment of switching on the multiplier with the front of the input signal and, consequently, the long process of switching on the multiplier, which leads to a reduction in the measurement time or an increase in the duration of one measurement cycle.

The closest to the proposed magnetometer consists of a sensor, amplifier limiter, phase detector, filter

Q low-frequency, controlled oscillator, divider, trigger, regulator of current magnitude in the sensor, indicator of current termination in the sensor, polarization current switching circuit and control device 3.

The main drawback of the circuit is

5 lack of reliable synchronization of the multiplier in the whole range of measured fields due to the inaccuracy of manual adjustment of the start time of the precession signal, as well as the inability to obtain a large multiplication factor (1000 or more) due to the uncertainty of the moment. the range of measurable fields due to the exponentiality of the transition process

switching on the current of polarization, which does not allow synchronization of the multiplier with an accuracy of several degrees, which is necessary with a multiplication factor of 1000 or more and an instrument readout accuracy of 0.1 nT during measurement cycles of 0.25 or less.

The purpose of the invention is to improve the accuracy and speed of measurements.

This goal is achieved by the fact that a proton magnetometer containing a series-connected command device, a polarization current driver, a sensor, an amplifier-limiter, a frequency multiplier made in the form of a series-connected phase detector, a low-pass filter, a controlled oscillator, and a frequency divider whose output is connected to the second input of the phase detector, as well as the counter, the first input connected to the output of the controlled generator, and the second input to the second output of the command device , The control unit is provided with a divider having a first input coupled to the output of the limiter and the second input - to a third output of the control device, and an output - to a second input of the frequency divider.

Functional diagram of the device shown in the drawing.

The device contains a sensor 1, a limiting amplifier 2, a frequency multiplier 3, a phase detector 4, a low-pass filter 5, a controlled oscillator 6, a frequency divider 7, a counter 8, a polarization current generator 9, a command device 10, a control unit 11 divider.

The device works as follows.

To ensure synchronization of the moment of switching on the multiplier 3 with the front of the input signal and ending the counting time, the divider control unit 11 sends a command to stop the resolution from the command device 10, and the first after the command from the positive front of the amplifier 2 limiter stops the frequency divider 7, which continues all the time pollation. At the end of the polarization and transient processes, when the output of the amplifier-limiter 2 appears again, the signal

the divider control unit 11 receives the command for terminating the stop and the first after the command the positive edge of the signal e of the amplifier-limiter 2, the frequency divider 7 is restarted, thus

at the time of stopping, information about the phase difference between the signal from the amplifier-limiter 2 and the signal of the frequency divider 7, which is stored in it for the entire polarization time, i.e., is stored in the frequency divider 7. the output time of multiplier 3 out of synchronism, when turning on the same frequency divider on the next cycle, a pulse at the output of frequency divider 7 appears through the time corresponding to the phase difference on the previous cycle, with an accuracy

determined by the instability of the controlled generator 6 and the inertia of the open-loop system phase-locked loop.

Claims (3)

1. US Patent No. 3546574, cl. 324-5, 1971. 2. Proton magnetometer YMP-3 (61D.2.733.000FO) “Kazgeofizpribor. five 3. US patent No. 3443207, CL. 324-5, 1969.