DEVICE RECORDING MAGNETIC FIELD Russian patent published in 1999 - IPC

FIELD: magnetic measurements, detection of object made from ferromagnetic materials. SUBSTANCE: device incorporates generator, inductance coil, measurement bridge with two magnetosensitive magnetoresistive elements and narrow band selective amplifier connected to output of bridge through blocking capacitors. V-shaped volt-oersted characteristic of bridge makes it possible to conduct modulation of amplitude of first harmonic of biasing field by recorded constant or low-frequency magnetic field. Narrow-band amplifier tuned to frequency of specified harmonic provides for level of amplitude-modulated signal required for subsequent detection. EFFECT: increased sensitivity, reduced noise and decreased energy consumption. 4 dwg