Victor Company of Japan, Limited

Fumiaki Ohno

Tsuyoshi Ono

Masatsugu Kitamura

Hideo Onoye

Yukihiro Kishima

Yutaka Morita

A separation band detecting circuit is used in an automatic program selection record player which has a photodetector which moves together with a tone arm and comprises a light-emitting element for emitting light against the surface of the record and a photosensitive element for receiving the light reflected at the record surface and producing an output in accordance with the light quantity of the received reflected light. The detecting circuit comprises an operational amplifier supplied with the output of the photodetector to its one input terminal, and a time constant circuit connected to the other input terminal of said operational amplifier, for giving a threshold level with respect to the operational amplifier and giving a time constant with respect to the level fluctuation in the threshold value. The time constant circuit varies the threshold level with a time constant, according to an input signal level to the one input terminal of the operational amplifier. The operational amplifier inverts its output when the relationship between amplitudes of the input signal level and the threshold level reverses.

Separation band detecting circuit in an automatic program selection

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.

Programmable automatic record player

A record disc playing apparatus comprises a horizontal drive motor for imparting a horizontal rotational force to a tone arm an address signal generating device for generating an address signal corresponding to a horizontal rotational angle position of the tone arm and a control device including a memory device for storing the magnitude of an inside force to be produced on the tone arm in correspondence with the horizontal rotational angle position of the tone arm. The address signal generating device supplies the generated address signal to the control device. The control device reads out the magnitude of the inside force from the memory device corresponding to the supplied address signal, produces a signal for cancelling the inside force at the rotational angle position of the tone arm corresponding to the read out magnitude of the inside force and supplies the same to the horizontal drive motor.

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Fujisawa, Japan

Fumiaki Ohno