| 摘要 |
PURPOSE:To prevent a moire distortion, etc., from occurring, by bringing white noise to FM modulation and forming an erasing signal having a prescribed deviation, increasing it gradually to the outside of a frequency band and writing it plural times to a track in which it has been written already. CONSTITUTION:An erasing signal being white noise, which has been sent out of a white noise generator 1 for utilizing an output at the time of no-signal of an FM demodulator and has been modulated by an FM modulator has a prescribed deviation. This erasing signal is written plural times in a track 6a on a floppy disk in which a color video signal has been written already, in a state that a frequency of its carrier is increased gradually to the outside of a frequency band from the inside of the frequency band of a video signal. In this way, a spectrum of a frequency of a sweep end does not remain behind as in case of a sweep erasion, and an erasion can be executed satisfactorily without making a moire distortion, etc., occur on a reproduced screen of a rewrite video signal.
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