ANTI-ALIASING FOR FREQUENCY OUTPUT SENSORS

摘要

A technique for reducing the effects of aliasing in a frequency output sensor system. The system includes a sensor for producing a sensor output signal at a frequency that varies within a modulation range as a function of an input parameter. The system also includes a processor for measuring the frequency of the sensor output signal at a sequence of sample times. The invention provides an analog filter for filtering the sensor output signal. In a first embodiment, the filter has an increasing phase lag versus frequency characteristic within the modulation range. In a second embodiment, the filter comprises a phase lock loop having frequency dividers in the input signal path and in the feedback path.