| 摘要 |
1,180,885. Recording and playback. INTERNATIONAL BUSINESS MACHINES CORP. 2 July, 1968 [17 July, 1967], No. 31503/68. Heading G5R. A helical-scan tape recorder has means for clamping sections of the tape independently of one another and for buffering such sections from one another which are operated in synchronism with the rotation of the magnetic head so that any section of the tape being transduced is clamped and each unclamped section is advanced. As shown, a timing plate 81 rotating with the head 11 connects a vacuum pump 51 in sequence to the input and output sections of a vacuum capstan 35, brakes B1 to B4, and buffer cavities 17, 43, so that semicircular sections 21, 22 of tape 20 are clamped and advanced in turn. A light source 61 rotating with the head 11 is detected by a photo-electric device 62 to control the head drive motor 60a in conjunction with synchronizing signals 63a picked up from the tape 20 by a fixed head 64. To give a still television picture, the tape may be held stationary so that the head 11 repeatedly scans the same track. |
