摘要 |
PURPOSE:To make bearing calculation and demodulation possible and make circuit constitution simple by performing the frequency analysis by complex inputs in the band centering at the frequency conversion signal near the carrier frequency. CONSTITUTION:The signal f1' of the same conversion frequency omega' as carrier frequency omega and the signal f2' of a 90 deg. phase difference therefrom are generated by a frequency conversion signal generating circuit 2', and the multiplying of the signal (c) from the sensor and the conversion signals f1', f2' is accomplished in a multiplier 7, whereby the demodulation signals g1' and g2' are obtained. When these signals are applied to a frequency analyzing part 8, the real number signal ma1' and imaginary number signal mb1', the real number signal ma2' and imaginary number signal mb2' are obtained. These signals are applied to a bearing calculating part 10. In the part 10, the differential frequency DELTAomega between the carrier frequency omega and the conversion frequency omega' and a phase error psi' are obtained, based on which the bearing is calculated. |