| 摘要 |
PURPOSE:To perform good phase servo by a method wherein the phase of the final CTL pulse is preserved even if CTL pulses drop out during playback and the phase is corrected by a change in the phase of the following tape phase- shifting pulses. CONSTITUTION:A phase servo circuit is provided with a phase detetor 23 detecting the phase differene between a reference phase and reproducing CTL pulses, a phase detector 24 detecting the phase difference between the reference phase and FG (frequency generator) pulses from the frequency generator related to tape phase shift and a phase detector 25 detecting the phase difference between the reference phase and FG pulses around the reproducing CTL pulses. The output in each phase detector 23-25 is fed into an arithmetic circuit 36 and the output in the phase detector 24 is added to the output in the phase detector 23 in this circuit. Furthermore a phase error is detected by deducting the output in the phase detector 25. In this way, when the CTL pulses drop out during playback, the value correcting the value at the final CTL phase pulse by a variation in the following FG phase pulses is picked out from the arithmetic circuit 36. |
