Video signal processor

A video signal processor comprising:

• a frequency modulator for outputting a frequency-modulated signal of a luminance signal input thereto;
• a frequency discriminator, which receives a reference frequency signal and the frequency-modulated signal and outputs a first or second error signal every horizontal or vertical scanning interval, the discriminator outputting the first error signal if a ratio of a frequency of the frequency-modulated signal during a horizontal- or vertical-sync signal interval to a frequency of the reference frequency signal is smaller than a predetermined ratio, the discriminator outputting the second error signal if the ratio is greater than the predetermined ratio;
• and
• a frequency controller for outputting, responsive to the first and second error signals, a control signal to the frequency modulator,
• wherein if the first error signal has been input to the controller a preset number of times or more during an interval before the second error signal is input thereto, the controller instructs the modulator to increase the frequency of the frequency-modulated signal, and
• wherein if the second error signal has been input to the controller a preset number of times or more during an interval before the first error signal is input thereto, the controller instructs the modulator to decrease the frequency of the frequency-modulated signal.