| 摘要 |
PURPOSE:To prevent beat disturbance to video signal despite proximity disposition of recording, playback and erasing heads by differentiating the FM-modulated luminance signal to be recorded to erasing current for video tracks and supplying this to the erasing head. CONSTITUTION:A differentiating circuit 30 is provided to the post-stage of a high- pass filter 20, and the FM-modulated luminance signal or the signal obtained by the high-pass filtration of this signal is differetiated and is supplied to an erasing head 3 through a rotary erasing amplifier 30. The frequency characteristics of the circuit 30 are made into such characteristics in which the cutoff frequency is made to the frequency higher than the white peak of the video signal S. Hence, the low- band components are lowered and removed roughly at 6dB/oct and only the high- band components are filtered by the circuit 30. The recorder is so constituted that the differentiated waveform of such characteristics is supplied to the head 3 through the amplifier 31. Thereby, the occurrence of beat disturbance to the video signal owing to fog is prevented despite the proximity disposition of a recording-playback head 2 and the head 3. |
