Abstract: A target tracking radar system for a guided missile wherein sum and difference signals from a reception antenna are multiplexed at a variable rate into a single channel receiver, the multiplexing rate depending on an alternating reference signal. The output of the receiver is applied to a phase sensitive detector operating in synchronism with the alternating reference signal and whose output is utilised to guide the missile towards the target. The detector output is also integrated and applied to circuit means which produces the reference signal, thereby forming a closed loop. The integrated detector output is also applied to a servo motor which drives the antenna to track the target.

Abstract: A radio system employs a method of controlling the transmitted power of a radio signal such that a minimum power level for efficient reception is maintained. Data is simultaneously transmitted between two radio stations using an error correction code. Each block of the code is accompanied by a power bit. The transmitted power bit is set high or low in dependence upon whether the number of errors in a sample of received blocks, as determined by processing of the received code, is equal to, above or below a predetermined threshold value. At the other station the received power bit is directed to a power control device and used to adjust the output power of the transmitter of that station by continuously variable slope delta demodulation.