| 摘要 |
<p>PURPOSE:To keep the frequency of a horizontal period signal in a video signal reproduced by a rotary head roughly constant, and to suppress the disorder and fluctuation of a reproducing picture by setting a rotating speed of the rotary head in accordance with a running speed of a magnetic tape. CONSTITUTION:At the standard reproducing time, a signal phase reproduced by a control head based on a reference signal S of a reference signal generating circuit 29 as a reference, and the rotary phase of rotary heads 2, 3 are maintained as prescribed. At the search reproducing time, a frequency dividing ratio N is set by a frequency dividing ratio setting circuit 19, and a magnetic tape 1 runs at a speed of N times of that of the standard reproducing time. An f-V converter 30 is set to a characteristic corresponding to the frequency of a frequency signal F1, and a drum motor 4 is brought to speed control by a signal F2. Also, the circuit 29 is controlled by the signal F1, and generates a signal S' of a frequency which is equal to a head switching signal SW. The signal S' and SW are brought to phase comparison by a phase comparator 15, supplied to a motor driving circuit 11 through an adder, and the motor 4 is brought to phase control. In such a way, the disorder and fluctuation of a reproducing picture can be suppressed.</p> |
