Apparatus for controlling linear tracking arm in record player

摘要

A control system for a linear tracking arm (11) in a record player. A signal representative of a tracking error angle of the arm is, after AID conversion, supplied to a microprocessor 14) for producing a control signal which controls an arm drive (15, 16) device so that the tracking error angle constantly remains zero. For invalidating an offset quantity possibly produced in the output of the tracking error angle detecting sensor due to changes in the characteristic thereof, a signal produced by the sensor when the arm is lifted in precedence to the playback operation is stored in a memory of the microprocessor. During the playback, the tracking error angle is detected with reference to the stored value. An average moving speed of the arm is measured for discriminating transient increasing in the speed of the arm caused by eccentricity of the disc from the increasing of the speed caused by the arm entering a lead-out groove of the disc.