In a telemetry system for use in an engine, a circuit structure (34) affixed to a moving part (20) of the engine is disposed for amplifying information sensed about a condition of the part and transmitting the sensed information to a receiver external to the engine. The circuit structure is adapted for the high temperature environment of the engine and includes a differential amplifier (102, 111)having an input for receiving a signal from a sensor (101, 110) disposed on the part. A voltage controlled oscillator (104, 115) with an input coupled to the output of the amplifier produces an oscillatory signal having a frequency representative of the sensed condition. A buffer (105, 116) with an input coupled to the output of the oscillator buffers the oscillatory signal, which is then coupledto an antenna (26) for transmitting the information to the receiver.