| 摘要 |
A sensor such as a quartz angular rate sensor is operated in a closed-loop mode including feedback of a control signal. The sensor produces a modulated carrier frequency signal. For stable operation of the feedback loop, the control signal is obtained from the modulated carrier frequency signal by complex demodulation of the modulated signal to produce an in-phase demodulated signal and a quadrature-phase demodulated signal, and the in-phase demodulated signal and the quadrature-phase demodulated signal are filtered by a complex equalizing filter to produce an equalized in-phase signal and an equalized quadrature-phase signal. The equalized in-phase signal represents information sensed by the sensor, and phase of a demodulation reference signal is adjusted to minimize appearance of the information in the equalized quadrature-phase signal. The equalized in-phase and quadrature-phase signals are complex modulated at the carrier frequency to produce the control signal. To compensate for variable delay or phase shift through the feedback loop, the phase of the control signal is adjusted by a phase adjustment signal. For equalization of an angular rate signal from a quartz angular rate sensor, the complex filtering includes compensation for peaking at the drive fork resonant frequency, compensation for secondary modes of vibration of the drive fork, and phase lead compensation for a relatively flat frequency response over the bandwidth of the angular rate signal.
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