Variable threshold comparator interface circuit

摘要

A signal processing circuit includes a comparator having a fixed and a variable reference input for detection of a positive quasi-sinusoidal waveform pulse. A signal detection circuit includes a low pass input filter, a voltage input clamp, a variable detection threshold, and a zero crossing detector. The circuit produces an approximately square wave output substantially coinciding with the positive pulse of the quasi-sinusoidal waveform received, from a variable reluctance sensor. The circuit has a positive to negative zero crossing detector armed by a variable threshold of the positive quasi-sinusoidal pulse, thus providing variable noise immunity and a fixed phase relationship between the input and output signal for an input signal having a variable amplitude.