| 摘要 |
PROBLEM TO BE SOLVED: To prevent linked occurrence of an azimuth error, even when an offset voltage is generated inevitably in a voltage outputted from an amplifier in a magnetism detection circuit. SOLUTION: A voltage generation part 11 applies the first and second voltages having inverted polarity to a sensor part 12. The sensor part 12 outputs a voltage value corresponding to a change of geomagnetism. A bias magnetic field generation part 16 applies an alternating-current bias magnetic field to the sensor part 12. A detection part 13 detects respectively voltages generated when the alternating-current bias magnetic field is applied in the positive and negative directions relative to the first and second voltages. The offset voltage outputted from the magnetism detection circuit is erased by taking the difference between the detected voltages. COPYRIGHT: (C)2006,JPO&NCIPI
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