MAGNETIC FIELD SENSOR UNIT

PROBLEM TO BE SOLVED: To provide a magnetic field sensor unit capable of attaining high sensitivity having resolution of an order of 10-7Oe or more. SOLUTION: The first repetition signals distributed by a distributor 2 are input respectively into an MI sensor element 3, and an attenuator and phase shifter 4. One of the second repetition signals distributed by a distributor 6 is mixed with an output signal from the MI sensor element 3 in a mixer 7, the other of the distributed second repetition signals is mixed with an output signal from the attenuator and phase shifter 4 in a mixer 8. Only components of a prescribed frequency or less in signals output from the mixers 7, 8 are passed through by low-pass filters 9, 10. A time interval counter 13 measures, as a time difference, a phase difference Δ between an output signal from an amplifier 11 indicated by a signal waveform a and an output signal from an amplifier 12 indicated by a signal waveform b, so as to detect a magnetic field. COPYRIGHT: (C)2005,JPO&NCIPI