Sensor amplification and enhancement apparatus using digital techniques

摘要

There is disclosed a digital enhancement circuit which responds to the complementary inductance provided by a planar coil sensor which inductance varies in a complementary manner according to the position of a movable member associated with the planar coil configuration. The complementary inductance is coupled to an oscillator whereby the period of the oscillator is varied in a first mode according to a first inductance value and in a second mode according to a second inductance value. These signals are then processed by means of digital processing circuitry to develop a signal indicative of the difference of the periods as divided by the sum of the periods. This signal is a ratiometric signal, and by employing digital counters, one can provide an output signal having a predetermined gain factor and having the above noted ratiometric characteristic which signal is indicative of the position of the movable member as further enhanced by the gain factor.