JPS6446342A - Block synchronization detection circuit - Google Patents

Abstract

PURPOSE:To simplify the constitution of a circuit, by performing the parallel conversion of a series input signal by shifting by one bit inputted to a serial- parallel conversion circuit by a hunting pulse. CONSTITUTION:The series input signal 5 is inputted to the serialparallel conversion circuit 1, and after being converted to a parallel 8 bit signal by a clock supplied from a one bit shift circuit 4, is fetched in an adder circuit 2, and decided whether or not the number of '1's is equal to that of '0's. And when the number of '1's is equal to that of '0's, '1' is outputted, and when it is not, '0' is outputted. Ordinary front protection and rear protection are performed by a synchronization protection circuit 3, and the hunting pulse is sent to the one bit shift circuit 4 when an asynchronous state is set, and the one bit shift of the parallel signal by the serial parallel conversion circuit 1 is performed at the circuit 4. In such a way, it is not required to add a synchronizing bit separately, and it is possible to realize a block synchronization detection circuit by the circuit with comparatively simplified constitution.