| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain full effect for rolling of a reproduced picture without requiring parts such as a port for exclusive use for a control microcomputer, a diode for compensating drum voltage and the like, in intermittent slow control of a VTR. <P>SOLUTION: As the relative speed between a magnetic tape and a magnetic head is increased at the time of starting intermittent slow control, the rotational speed of a drum must be increased. Then, a control output PWM is made by making a value in which the prescribed value is added to an indication value of the normal rotational speed as PWM data, and compensating control is performed at the time of start. Thereby, even if an operation point of a drum motor is deviated by variation of PWM data in the normal rotational speed, constant speed compensation is always performed. Also, as a relative speed is varied when a capstan motor is damped and rolling of a reproduced picture occurs, rolling is compensated by subtracting the prescribed value from drum control PWM data in the normal rotational speed. Further, when a mode is shifted to an intermittent mode, after synchronizing with an external synchronizing signal is finished, the capstan is started, and the PWM control is performed. <P>COPYRIGHT: (C)2004,JPO</p> |
