| 摘要 |
<p>PURPOSE:To make it possible to effect the most proper constant tape advancement, while reducing the wow and flutter, by controlling the speed of a capstan driving DD motor with the output of capstan rotating speed detecting means in order to effect the constant tape advancement. CONSTITUTION:During the forward advancement of a tape, the rotor 6 of a DD motor 1 is turned counter-clockwise whereas one pinch roller 17 is forced, as shown in solid lines, into contact with a capstan 4 to hold and advance the tape T at a constant speed in the direction of arrow a. The other pinch roller 18 is separated, as shown in solid lines, from a capstan 9. Moreover, the rotating speed of the DD motor 1 is controlled constant with the output of rotating speed detecting means 15 which is mounted on the outer circumference of a gear 13 fixed integrally to the rotor 6. During the backward advancement of the tape T, the rotations of the DD motor 1 are interchanged into counter-clockwise ones so that a fly-wheel 10 is turned clockwise by means of a belt 11 and so that a capstan 9 is also turned clockwise. At this time, the speed of the motor 1 is controlled with the output of rotating speed detecting means 16 which is mounted on the outer circumference of a gear 14 fixed to the fly-wheel 10.</p> |
