| 摘要 |
PURPOSE:To set up tape speed at the time of reproduction and to stabilize a servo system by using a counter carrying output and an upper and lower limit discriminating output at digital detecting characteritics to obtain a mute output from the carry output. CONSTITUTION:In an AFC circuit in a servo system for a VTR rotary head disc motor, a vertical synchronous signal V is inputted to a vertical syntheonous signal input terminal 11. t the time of a VTR regenerative mode, a reproducing control pulse CTL is inputted to an input terminal 12. An output from a latch circuit 25 latching the lower 11 bits of a down counter 24 is inputted to a digital/analog converter 27. The output of the digital/analog converter 27 is used as a rotation controlling signal for the rotary head disc motor. If the reproducing control pulse CTL is not inputted, the down counter 24 continues to count down and output carry. After passing a fixed period, a flip-flop circuit 45 is driven and the output of the circuit 45 is used as a mute signal. |
