An intracorporal telemetry for strain gage transducer

Abstract

A new strain gage bridge to PPM (Pulse Position Modulation) converter has been developed. It consists of a chopper amplifier and a voltage to time converter associated in a feed-back loop. This topology exhibits mainly an automatic offset cancellation capability, a ratiometric transfer function and an accuracy of 10 bits. Therefore, this converter is insensitive to offset drifts, and is well suited for long term monitoring of orthopedic implants.