JPS59104508A - Bearing detector of terrestrial magnetism - Google Patents

Abstract

PURPOSE:To make a stable and precise measurement possible without the variation of a bearing indication value due to various noises, by using a low-pass filter effectively to realize the stabilization of a bearing detection signal. CONSTITUTION:The output of an output amplifier 4 of a magnetic bearing detecting coil 3 is inputted to a low-pass filter 11 and noise components are eliminated. The output of a comparator 5 is supplied as the reference input of a phase comparator 12 and is compared with the phase of the output of a VCO 14. If they have a phase difference, the output of the phase comparator 12 is increased or reduced. Since this degree of increase or reduction is smoothed and delayed by a low-pass filter 13 of the next stage and is supplied to the VCO, the action of tracking of the output frequency of the VCO 14 upon the comparator output is made gentle. Therefore, an averaged output of the outputs of the comparator 5 is transmitted to the output of the VCO, and the indication value is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application and Prior Art) The present invention relates to direction measurement using a magnetic detector, which is commonly used to measure the direction of ships and vehicles.

Conventionally, as this type of circuit, a device as shown in FIG. 1 exists. That is, the output of the geomagnetic direction detection coil 3 located so as to surround the magnetic material 2 such as permalloy rotated by the Hall motor 1 is amplified and detected by the detector 4 as shown in FIG. and is shaped into a rectangular wave B with a 360 degree period as shown by the dotted line in FIG. 2a. On the other hand, the azimuth signal of the measured azimuth (directed toward the neck in the array i'-L%) obtained from the Hall element of the Hall motor 1 is shaped as shown in FIG. B,
Both signals of b:i are supplied to the R-8 flip-flop circuit 7, and a rectangular wave signal shown in FIG. 2C is generated. Then, in the counting circuit 8, the width of the rectangular wave C is determined by the clock signal (i) generated from the clock signal generator 9 (Fig. 2d). Due to the noise, the waveform is actually distorted as shown in e of the same figure.For this reason, the output of comparator 5 is in a very unstable state near the zero cross point as shown in f. The point changes every time due to the influence of the power supply frequency, etc. Therefore, the rising (falling) position of the comparator 5 output (Fig. 2 B) always changes, and the display on the display is very unstable. It was stable.

(Purpose and Structure) The present invention eliminates this drawback, and will be explained below using the embodiment shown in FIG. Components with the same reference numerals as in FIG. 1 have the same functions, so their explanation will be omitted.

11i/i low-pass filter, and the direction signal is e.g.
For HZ, use one with an upper limit frequency of about 100 Hz, for example. The output of the low-pass filter 11 is supplied to a phase comparator 12 via a comparator 5. The phase comparator 12 compares the phases of the output of the comparator 5 and the output of a voltage controlled oscillator 14 (described later), and generates a voltage according to the phase difference. This output is supplied to a low frequency demultiplexer 13. The low-pass filter 13 is approximately 0 for one direction word (4QHz)
．． It has an upper frequency limit of 6 Hz. 14 is a voltage controlled oscillator (hereinafter referred to as VCO), and a low pass filter 13
It sends out an output whose frequency changes depending on the output voltage.

The output of the VOO 14 is supplied to the phase comparator 12 and also to the set gate of the seven lip-flop 7.

The other configurations are the same as in FIG. 1, so they are omitted.

(Function, Effect) In the device shown in FIG. 3, the output of the output amplifier 4 of the magnetic direction detector (FIG. 2e) contains noise as described above. However, since this noise component is removed by the low-pass U wave filter 11, there is only one zero-crossing point. Then, a stable and desired rectangular wave as shown in FIG. However, the rising (falling) position of this rectangular wave fluctuates from left to right as described above. This output is supplied as a reference input to the phase comparator 120, and is compared with the phase of the output of C014. If there is a phase difference between the two, the output of the phase comparator 12 is increased or decreased. However, this degree of increase/decrease is smoothed and delayed by the low-pass filter 13 in the next stage and is supplied to CO.
The tracking effect of the output frequency of the VCO 14 on the converter output becomes slow. Therefore, the average output of the comparator 5 is ultimately sent out as the output of the VCO, and the displayed value is stabilized.

In the embodiment, a combination of a coil and permalloy is used as the magnetic direction detector, but a Hall element, an M-type element, etc. can also be used.

As explained above, according to the present invention, since the direction detection signal is stabilized by utilizing a low-pass filter, stable and accurate measurements can be made without the direction display value fluctuating due to various noises. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a block system diagram of the conventional device, FIG. 2 is an electrical waveform diagram of the main part thereof, and FIG. 3 is a block system diagram of the main part of the device of the present invention.

Claims (1)

[Scope of Claims] A geomagnetic azimuth detector that generates an azimuth signal, and a low-pass filter with an upper limit frequency higher than the azimuth signal and higher than the noise frequency for removing high frequency noise components from the output of the geomagnetic azimuth detector. , a phase comparator that generates a voltage according to the phase difference between the output of this low-frequency A4 waveform generator and the output of the voltage controlled oscillator described below, and a phase comparator that generates a voltage according to the phase difference between the output of this low-frequency A4 waveform generator and the output of the voltage controlled oscillator described below, and the output of this phase compensator that is manually input and that is higher than the frequency of the above-mentioned direction signal. = A low-pass filter with one low frequency, a voltage-controlled oscillator that generates an output voltage with a frequency corresponding to the output of the low-pass filter,
A geomagnetic azimuth detector characterized in that the output of this voltage controlled oscillator is used as a geomagnetic azimuth detection output.