| 摘要 |
PURPOSE:To obtain a magnetic pattern in which horizontal synchronizing signals are in phase, by providing a circuit which delays a video signal corresponding to variations in the DC voltage of a rotary head driving motor. CONSTITUTION:A video signal S1 is inputted from an input terminal 1 and supplied to a delay circuit 5 through an LPF2, an AGC3 and a video amplifier 4. The video signal S1 is further supplied to a synchronous separating circuit 10, a frequency separating circuit 11 and a frequency divider 12 to output sample pulses S6. The rotary phase reference signal of a head motor 21, on the other hand, is inputted from terminals 16 and 17 to an FF15, and reference pulses S4 are applied to a phase comparator 13 through a trapezoidal-wave generating circuit 13, so that a signal obtained by extracting sample pulses S6 from a trapezoidal-wave S5 is supplied to a DC amplifier 18. On the basis of its output S3, a motor 21 is controlled through an oscillator 19 and a motor driving circuit 20, and with the output of the DC amplifier 18, a luminance signal passed through the delay circuit 5 is controlled and recorded 9. Thus, a magnetic pattern in which horizontal synchronizing signals are in phase is obtained. |
