MONITOR CIRCUIT IN CHANNEL SELECTING STATE OF PARALLEL FRAME SYNCHRONIZATION CIRCUIT

摘要

PURPOSE:To reduce number of monitor pins in the channel selection state independently of number of output channels by using a phase signal corresponding to a frame counter according to a state of a channel selection signal as a monitor signal. CONSTITUTION:A phase signal PH1 (or any of PH2-PHn) given to a decision circuit 9 from a frame counter 8 corresponding to an active signal S1 (or any of S2-Sn) among channel selection signals S1-Sn given from a channel selection circuit 5 to the decision circuit 9 is outputted from a monitor signal terminal 11. Then a frame pulse FP being a reference signal RS is outputted from a reference signal terminal 10. Thus, which of the channel selection signals S1-Sn is active is confirmed by comparing the both.