Synchronization system for use in digital transmission system

摘要

In a synchronization system for use in a digital transmission system in which an encoded digital transmission signal at least part of bits of which have specific statistic characteristics is transmitted, a digital transmission signal received by a decoder within a digital transmission apparatus at a receiving end is subjected to a decoding processing in units of samples on the basis of a synchronous input signal. The digital transmission apparatus at the receiving end includes a monitor for monitoring internal states of the decoder which vary between a synchronous state and an asynchronous state owing to the statistic characteristics of the digital transmission signal, a synchronization detector for determining whether the digital transmission system is in the synchronous state based on an output of the monitor, and a phase shifter for shifting a relative phase of the digital transmission signal against a synchronous input signal supplied to the decoder, one bit by one on the digital transmission signal in units of samples, in the case that a determination result of the synchronization detector indicates the asynchronous state.