HIGH FREQUENCY DIGITAL PCM DEMODULATOR

摘要

Apparatus is disclosed for acquiring and maintaining a generally continuous clock signal from a very high frequency encoded data stream of the type which is self-clocking and has logic state transitions occurring at two locations within each bit cell of the data stream. The apparatus is particularly useful in decoding apparatus, such as may be used in a magnetic recording and reproducing system. The apparatus effectively generates the clock signal from the encoded data stream and reclocks the data stream utilizing the generated clock signal to accurately position the logic signal transitions within the bit cells and thereby assure accurate decoding of the data. The apparatus processes two simultaneously transmitted synchronous data streams, and has the capability that permits the generated clock signal from one data stream processed in one channel to be used to maintain synchronization of the other processing channel notwithstanding a loss therefrom of the data stream for short periods of time.