JPS5711554A - Frame synchronizing system - Google Patents

Abstract

PURPOSE:To prevent out of frame synchronism, by detecting the momentary interruption through the provision of a memory circuit having a phase locked loop between a code conversion circuit and a frame synchronizing circuit and providing a means to stop out of the frame synchronism. CONSTITUTION:A consecutive clock of a signal from a trnamission line 3 is picked up by a code conversion circuit 1 for data reproduction. The reproduced data is written in a memory circuit 5 and read out with the clock from a phase locked loop 6 in synchronism depending on the clock from the circuit 1 to transmit the clock and the data to a frame synchronizing circuit. Even if momentary interruption is caused and the clock from the circuit 1 is interrupted, since the clock is supplied from the circuit 6, the count of a circuit 2 is not stopped. As the data in this case, since inaccurate information is transmitted to the frame synchronism, the out of frame synchronism can be avoided by the output of a momentary interruption detecting circuit 4.