Position finding system for video or sound disc - uses data stored in memory to compare distance between reference signal along track and required position

摘要

The position sensing system to obtain a selected point along the groove (2) of a disc (1) mounted on a turntable forms part of a sound reproducing device. The pick-up (6) which is connected to a signal processing unit (8), a gate (10) and a loudspeaker (11), is also connected to a lifting mechanism (7), and can be moved radially outwards or inwards. Another connection (15) at the pick-up is followed by a memory (12) an equaliser (13) and an input (14) for data which corresponds to the various points along the groove. When the pick-up is lowered and the turntable rotated, the system compares the distance between a position signal along the track and a stored signal for a required position, and adjusts the position of the pick-up by lifting, radial and lowering movements.