Abstract: In an optical disc apparatus reading and writing data with respect to an optical disc, a motor controller uses widest pattern signals outputted from an optical pickup for judging size of an optical disc mounted on a turn table and stop of rotation of the optical disc. Since an inverse number of the widest pattern signal has correlation with a frequency sensed by a conventional frequency generator, the motor controller calculates a difference between inverse numbers of the widest pattern signals before and after putting braking force to the turn table, and judges the size of the optical disc with reference to variation of rotation speed before and after the braking. The motor controller further calculates a prediction time when the rotation of the optical disc will be stopped with using the variation of the inverse number of the widest pattern signal, stops to put the braking force to the turn table at the prediction time, and judges the rotation of the optical disc has been stopped.
Abstract: In an optical disc apparatus reading and writing data with respect to an optical disc, a motor controller uses widest pattern signals outputted from an optical pickup for judging size of an optical disc mounted on a turn table and stop of rotation of the optical disc. Since an inverse number of the widest pattern signal has correlation with a frequency sensed by a conventional frequency generator, the motor controller calculates a difference between inverse numbers of the widest pattern signals before and after putting braking force to the turn table, and judges the size of the optical disc with reference to variation of rotation speed before and after the braking. The motor controller further calculates a prediction time when the rotation of the optical disc will be stopped with using the variation of the inverse number of the widest pattern signal, stops to put the braking force to the turn table at the prediction time, and judges the rotation of the optical disc has been stopped.
Abstract: A motor driver has a braking control circuit. The braking control circuit shuts off the supply of an electric current to the coils included in the motor when a motor control signal shifts to a predetermined level and, after a predetermined length of time secured in accordance with an index signal, starts application of braking to the rotation of the motor by the use of a braking circuit. The index signal is obtained from the signal that indicates the rotational position of the motor. The motor control signal is fed from a control signal generating circuit to the braking control circuit.
Abstract: A record player is provided with a turntable brake for instantly stopping the turntable of the record player in playback when desired and a pair of balance wheels for permitting slant of the turntable within a predetermined range when manually operating the turntable. The turntable hereof has a peripheral drum portion extending downwardly from its bottom and a rubber shoe is mounted on one end of a pivoted lever arm. The lever arm is adapted to be actuated to press the rubber shoe against the drum portion of the turntable for stopping rotating movement of the turntable by means of friction.