| 摘要 |
<p>SO 1375 A video signal reproducing apparatus of the helical scan type includes a guide drum having a magnetic head fixed thereto for scanning a magnetic tape wrapped about the guide drum, first and second capstan assemblies on opposite sides of the guide drum for moving the tape in a desired mode of operation, a manually rotatable wheel for controlling the speed and direction of movement of the tape in a track searching mode, signal generating apparatus for producing a speed pulse signal having a frequency corresponding to the speed of rotation of the wheel, a flip-flop for producing a direction signal corresponding to the direction of travel of the wheel, a tape tension detector engaging the magnetic tape for detecting the amount of tension on the magnetic tape at a point adjacent the guide drum, a pulse control circuit for producing take-up and supply drive clock pulses in accordance with the amount of tension detected by the tape tension detector and the speed pulse signal, and take-up and supply capstan drive circuits for controlling operation of the first and second capstan assemblies, respectively, in response to the direction signal, the speed signal, and the take-up and supply drive clock pulses, respectively, wherein the tension on the tape as detected by the tape tension detector is controlled to be within respective predetermined ranges during movement of the tape in the forward, reverse and stop modes of operation.</p> |
