| 摘要 |
<p>PURPOSE:To facilitate tracking preset operation by adjusting the phase difference between a drum servo system reference signal and a playback capstan servo system based upon a vertical synchronizing signal from a control head according to an FM video signal during reproduction. CONSTITUTION:During recording, the vertical synchronizing signal separated from a video signal is sent to a capstan motor 23 through changeover switches 9 and 12, and a holding circuit 29 to rotate a capstan at a specified speed. Pulses which synchronize with the rotation are applied to control head 4 through a monostable multivibrator 13. During reproduction, playback control pulses for a capstan servo system from the head 4 supplied to the holding circuit 29. Then, the time constant of a monostable multivibrator 44 is adjusted to maximize a playback FM video signal, and then the phase difference between the held pulses of the circuit 29 and reference pulses for a rotary drum servo system from an FF17 is the same with the recording, performing tracking preset operation easily.</p> |
