Programmable automatic record player

摘要

A pickup arm is equipped with a photo sensor assembly for detecting non-recorded portions on a disk. The sensor is located in such a position that horizontal distance between the stylus tip and the detecting point of the sensor measured in the direction of the radius of the turntable is substantially constant throughout the possible rotational angle of the arm. The rotational angle of the arm is measured and is modified by a given angle corresponding to the above mentioned distance. When this distance deviates from a standard value on replacement of the same with another, the variation may be readily corrected by manipulating a potentiometer. Prior to performing an automatic playback, the disk is scanned by the sensor and signals indicative of the arm angles corresponding to the non-recorded portions are stored. After scanning, the arm is controlled by comparing the actual angle of the arm with the prestored angles, to place the stylus on a right position on the disk to perform automatic playback in accordance with programmed information.