| 摘要 |
PURPOSE:To obtain an automatic music selecting device which is simple in construction and is superior in precise music selection having high efficiency of reproduction, by providing a sensor part consisting of a light emitting source and two photodetecting elements arranged in a head shell, a specific detector for a zone where no voice groove, and a circuit part. CONSTITUTION:A light emitting source L is arranged obliquely over a stylus tip 3, and a sensor part consisting of two photodetecting elements PT1 and PT2 arranged at a left and a right symmetric positions across a shielding plate and at higher height from a record surface 8 than that of the light emitting source L is provided. Further, the photodetecting elements PT1 and PT2 are connected into an electric bridge circuit mode; and a device which pull out the electric output signal of the bridge, then providing a device which detects a zone where no voice groove is provided by obtaining a voltage output of an AC waveform having a zero-potential point at an adequate position on said zone, and a circuit part which holds an arm accurately at the zero position by operating a horizontal rotation control mechanism at said zero position and then moves up and down a pickup arm at the position. |
