SPECTRUM ANALYZER FOR LOW MAGNETIC-FIELD

A device to obtain an estimate of the spectrum of a time-variable magn etic field has been developed. The amplitude of each spectral componen t of the magnetic field series is obtained by analyzing with a double demodulation technique the signal generated from a flux-gate-like dete ctor operating in open loop configuration. This device shows a sensiti vity of about 1 mV/nT in the range from 0 to 300 Hz. For frequencies h igher than 300 Hz the sensitivity decreases, and a correction factor t hat depends on the transfer function of the electronic device must be applied. The present device can be applied to environmental measuremen ts, industrial applications, traffic control, and scientific research. (C) 1995 American Institute of Physics.