Data transmission systems

摘要

A communicating network in which encoder/decoders are joined in a ring by transmission links. Data passes over the links as a carrier having two cycles per bit period. The amplitude of the carrier in any bit period is non-zero and represents the value of the bit. In each encoder/decoder the carrier is recovered by a tuned circuit, the clock is recovered by dividing the carrier and the data is recovered. The same carrier is remodulated with the output data. The whole system forms an oscillatory system which sustains the carrier at a frequency which varies if the properties of the ring change. The specification also describes the use of a modulated carrier in conjunction with a filter blocking frequencies below 25 MHz to give good noise immunity.