| 摘要 |
PURPOSE:To attain stable reproduction for variable integral number times of speed search, by D/A converting double speed information, and adding the result to a capstan control signal for preventing a noise bar position from being unlocked. CONSTITUTION:A CFG signal generator 12, a CFG amplifier 13, a b-v converter 15 and a driving circuit 23 constitute a speed control loop used for a VTR system and a control head 17, a CTLP amplifier 18, a pulse generator 20, a phase comparator 21, and a driving circuit 13 constitute a phase control loop, and a stable tape running is executed by the added signal of both the loops with an adder 22. Frequency dividers 14, 19 change the reproduction double speed into an integral number of multiple by changing the frequency-dividing ratio. The digital quantity of a digital quantity holding device 26 is changed freely with an external signal, and this change corresponds to the change in the search speed. In this system, a small amount of correction at a low speed is summed to the control input of a capstan motor driving circuit 13 and a large amount of compensation at a high speed is added to it for fixing bar noise. |
