A magnetometer for digital analysis of a magnetic field is presented. The method of measuring is based on the detection of the coil relaxation time, after its excitation up to saturation by means of short current pulses. The time detection uses a voltage limiter, before an active comparation. An external magnetic field causes a width modulation of the relax-pulses, due to the total consumption of the supplied energy. The width of the relax-pulses is evaluated by counters and, after buffering, picked up to IBM/PC parallel I/O. The sensitivity of the present magnetometer is 10 nT from DC up to 500 Hz and 100 pT up to 5 Hz, in real time. Data analysis could be utilized for autonomical navigation systems, as well as for an industrial, environmental and medical use.
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