Kabushiki Kaisha Toshiba

Takayuki Uchida

Takuji Yoshida

Hiroshi Nakane

A disc reproducing system having a pickup for reading data recorded on a disc that is rotated by a disc drive motor. The system, also has a clock signal generator for generating a clock signal that is phase-locked with the data read by a pickup, and a processor for processing the data read by the pickup based on the clock signal generated by the clock signal generating means. Further included in the system is a linear velocity signal generator for generating a linear velocity signal with a frequency that is related to the rotational speed of the disc, a servo controller for controlling the rotation speed of the disc drive motor so as to keep constant a relative speed between the pickup and the disc, and a pickup feed motor for moving the pickup in the radial direction of the disc. The apparatus is characterized by the fact that a capture range of the clock signal generator can be controlled to meet the clock signal with the data read by the pickup at a completion of the pickup feed operation.

Track jump servo apparatus for disc reproducing system

The present invention relates to a digital data processing apparatus for transferring digital data which is output from a disc reproduction section (15.sub.1) to a buffer memory (18)-equipped host processing section (13) and for making processing. By detecting a shift in frequency of an operation clock on the basis of an output of the disc reproduction section (15.sub.1) and varying the frequency of the operation clock of the host processing section (13) in accordance with a result of that detection, it is possible to prevent the memory (18) from being placed in an over- or an underflowed state and to perform a normal data reproduction.

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Kumagaya, Japan

Takayuki Uchida