Waveform encoded altitude sensor.

摘要

The Fig. represents a spread spectrum waveform encoded altimeter. Spread spectrum carrier wave signals which are transmitted and later received are processed in a detecting apparatus which includes a plurality of individual detectors (48 to 54). A pair of detectors (48, 49) is provided to detect an early chip or signal. Another pair of detectors (53, 54) is provided to detect a late chip. A pair of edge chip detectors (51, 52) for detecting the centre or locked on chip may also be provided. Logic circuits (61 to 72) are employed to sum the voltage signals from the detectors (48 to 54) and to provide a control signal capable of adjusting a tracking generator (42) to enable it to lock on to the received signal. An altimeter counter is provided which is started by a unique chip in the transmitted signal and stopped when the same unique chip is dectected in the receiving and tracking loop.