Sound or video replay disc unit - has independent search and replay mechanisms using two separate magnetic units

摘要

Independent search and replay mechanisms take into account the different requirements for these two operations, providing fast and precise direct access to an address without the need for space wasting gaps between recorded sections. The two magnets (7,8) which are mounted on a revolving carrier (4) are energised from two independent sources (U1,U2). One magnet (7) provides coupling via a ring (9) to a motor (M1) for the search operation whilst the second magnet (8) activates a coupling (12) driven by a second motor (M2). The search motor (M1) is a low inertia d.c. motor whilst the play back motor (M2) is a synchronous motor. Magnets (7,8) have exceptionally low time constants.