DISC REPRODUCING SYSTEM FOR COMPENSATING MECHANICAL IMPERFECTIONS

摘要

The invention disclosed is primarily concerned with reducing the effect of spurious vertical deviations in the groove of a phonograph disc which result principally from record warp. Such imperfections can cause significant degradation of the reproduced signal. The playback apparatus of the invention comprises a turntable and cartridge having a stylus and a sensor which senses vertical deviations of a disc on the turntable. The sensor controls the operation of an actuator which moves the disc in a direction to eliminate vertical deviation of the disc at the cartridge. The sensor is substantially more compliant than the stylus and is arranged to sense an unmodulated part of the disc. The sensor may be formed as a second stylus. According to a preferred arrangement the sensor senses vertical deviation of the disc in close proximity to the cartridge and with respect to a vertically fixed reference.