| 摘要 |
PURPOSE:To obtain a stable slow motion picture without noise, by repeating playback and stop sections depending on normal playback speed on a magnetic tape, at the playback of slow motion. CONSTITUTION:A capstan motor 15 is switched in the order of start, constant speed and reversing brake and a direction detecting circuit 11 is operated when the motor exceeds slightly toward reversing to stop the drive. In this case, when a frequency of a two-phase frequency generator 14 having about 90 deg. phase difference provided for the capstan motor 15 is increased, the reverse rotation can be negligible. But, it is desirable for the processing with less number of poles of the generator 14, and if a reversing brake is activated, the direction detecting circuit 11 is operated with a slight delay from the point of time of a true revolution frequency ''0'' of the motor 15, to avoid the stopping of essentialy position. Thus, after the detection of direction with the output of a monostable multibrator 17, the motor is driven toward forward for a given time again, allowing to cancel the position shift. |
