HIGH DEFINITION TELEVISION SIGNAL PROCESSING CIRCUIT

摘要

PURPOSE:To prevent synchronization from being unlocked early even when the reception state is deteriorated by providing a MUSE-HD signal detection circuit to the processing circuit so as to unlock the synchronization early even when another input signal is selected thereby detecting a new frame pulse(FP). CONSTITUTION:A MUSE-HD signal detection circuit 9 detects an HD signal changing by a horizontal rate and detects whether or not the signal differs from a MUSE signal synchronized at present and outputs its resulting detection signal. A FP reset circuit 7 does not increment a reset counter when the circuit 9 detects it that the input signal is not changed and increments the reset counter when the circuit 7 detects it that the input signal is unchanged. When the counter is incremented by a prescribed number of times, the FP signal is outputted and an internal counter is reset by the FP signal detected from a succeeding FP detection circuit. Thus, even when another input signal is selected, the synchronization is quickly unlocked to detect a new FP signal and even when the reception state is wrong, it is prevented that the synchronization is quickly unlocked.