PURPOSE: To generate the reference signal through a simple circuit constitution and based on the horizontal synchronous signal synchronized with the video signal output in order to set and confirm the blanking duration plus the sink phase and duration of the video signal as well as the burst flag phase and duration each.

CONSTITUTION: The horizontal synchronous signal applied to input terminal 1 is supplied to blanking fall phase setting circuit 2 to deliver the signal featuring the phase variation through phase adjuster 7. The output signal of circuit 2 is differentiated at differentiating circuit 5 and then added to adder 6 after differentiation at differentiating circuit 4 via blanking rise phase setting circuit 3. At the same time, the output signal of circuit 2 is also supplied to sink fall phase setting circuit 8, and the output is added to adder 12 via differentiating circuits 10 and 11 plus sink rise phase setting circuit 9 each. The same precessing is applied also to the burst flag. Thus the blanking marker output is obtained from adder 20.