Y/C SEPARATING CIRCUIT

PURPOSE:To easily and correctly compensate the delay time of a glass delay line and also to prevent the deterioration of picture quality. CONSTITUTION:A composite video signal and an output composite video signal are respectively inputted to a burst phase comparator 44 and a color component amplitude comparator 62. The output corresponding to the deviation quantity of phase difference from the burst phase comparator 44 is given to gyrators 40 and 42 and the inductance value of the gyrators 40 and 42 is automatically adjusted for permitting the delay time of the glass delay line 26 to correctly become IH. The output corresponding to amplitude difference from the color component amplitude comparator 62 is given to a variable amplifier 36 and a non-standard detecting circuit 78, the gain of the variable amplifier 36 is automatically adjusted and also a trap circuit 76 is switched in accordance with an output value so as to make the decay rate of the trap circuit 76 change.