PURPOSE: To reduce remarkably a frequency shift width less than a conventional circuit without decreasing emphasis amount by providing pre-shoot and overshoot to a waveform when a video signal processor is used as the emphasis circuit for a frequency modulation/demodulation system.

CONSTITUTION: A signal is changed over at each 1H by the 3rd switch 14 and inputted to the 3rd memory circuit 19 and the 4th memory circuit 20. When a control signal applied to control terminals 32, 33 is at H level, the memory circuits 19, 20 store sequentially the inputted signal and when a control signal applied to the control terminals 32,33 is at L level, the said memory circuits 19,20 outputs the signal in an opposite time series as the stored time series. Since the waveform shown in Figure becomes a waveform having pre-shoot and overshoot, a waveform having a peak value lower than that of broken lines S is obtained regardless that the emphasis amount is the same as that of a conventional example.