| 摘要 |
In a video disc player, a stylus arm (24), carrying a track following stylus (20) at one end thereof, has its other end secured to a carriage by a compliant member (30). The carriage is translated along a path disposed radially of the disc record during playback. Pickup circuits (52) are employed for sensing the variations in a signal representative capacitance formed between an electrode incorporated in the pickup stylus and conductive material disposed in the record to recover pre- recorded information from a spiral track disposed on the record. A stylus position indicative capacitance (94, 98) established between a first electrode secured to the stylus arm and coupled to the pickup circuits and a second electrode mounted to the carriage in the vicinity of the first electrode, is provided. In an embodiment, the stylus position representative capacitance is formed between a signal coupling flylead (38) of the stylus and the second electrode which is mounted on a cartridge (32) housing the stylus in the carriage. Circuitry (108-112) is provided for sensing signals appearing at the output of the pickup circuits to generate a signal indicative of the position of the pickup stylus relative to the arm cage. The rate of translation of the carriage is varied (46) in response to the stylus position indicative signal to maintain a desired relationship between the pickup stylus and the arm cage. <IMAGE> |
