COLOR SYSTEM DISCRIMINATING CIRCUIT

PURPOSE:To offer the color system discriminating circuit giving stable operation without erroneous discrimination even under the weak electric field by discriminating whether or not the 'Lo' state of an ID signal is temporary and remaining unchanged when judging this phenomenon as temporary. CONSTITUTION:A synchronizing pulse generation circuit 55 generates a synchronizing pulse II to take the synchronization of rising by taking a clock CK of a period when an identification detection signal ID is 'Lo'. At this point, a mask pulse generation circuit 54 detects and judges whether or not the 'Lo' state of the identification signal ID is temporary, generating the mask pulse to mask the synchronizing pulse II when judged as temporary. Thus, the color discrimination signal ID synchronizing with the reference signal and not taking to 'Lo' when the identification detection signal ID becomes temporally 'Lo' can be obtained.