Patent ID: 6960945

Claim:
A high performance drive circuit for a capacitive transducer, said capacitive transducer including a pickup electrode and a first drive electrode, said pickup electrode having an associated voltage, said drive circuit including: oscillator means including an oscillator signal; voltage reference means including a first reference voltage output; buffer amplifier means including an output signal responsive to the pickup electrode voltage; synchronous demodulator means including first and second output signals responsive to said output signal of said buffer amplifier means; first and second signal storage capacitors, each of said capacitors storing an individual output signal of said first and second output signals of said synchronous demodulator means; differential amplifier means including an output responsive to the signals stored on said signal storage capacitors; feedback generator means including a feedback signal responsive to said output of said differential amplifier means; and a first drive signal, said first drive signal having an amplitude equal to the difference between said first voltage reference output and said feedback signal, and said first drive signal being synchronized in time with said oscillator signal, said first drive signal being operative on said first drive electrode.