Sony Corporation

Takeshi Hachimori

Mitsuru Okabe

Hidekazu Nakai

Hideki Ishikawa

A disc playback apparatus for playing back a disc on which data have been recorded under a CLV control is provided with a CLV control section for performing a CLV control, a speed comparator and a reference clock generator for performing a CAV control, a changeover switch for switching between the CLV control and the CAV control, and a CPU for setting a switching point of the changeover switch and controlling the switching of the changeover switch. According to another aspect of the invention, switching is made between a playback with a CLV servo control and a playback with a CAV servo control in accordance with the reproduction scanning position in the disc radial direction. In particular, a difference between disc rotation speeds at the disc innermost and outermost tracks is made smaller than that in a case where a playback is performed at a specific linear velocity over the disc entire area. According to a further aspect of the invention, regions are set by dividing the disc entire area in the disc radial direction. A judgment is made of a region to which a current reproduction scanning position belongs, and control is made so as to switch the playback linear velocity in accordance with the region thus determined. In particular, a difference between disc rotation speeds at the disc innermost and outermost tracks is made smaller than that in a case where the linear velocity is not changed over the disc entire area.

Apparatus and method for reproducing data recorded at a predetermined

A disc reproducing device and a disc reproducing method for reproducing a disc-shaped recording medium (combined disc) on which first data to be reproduced at a first reproducing rate and second data to be reproduced at a second reproducing rate faster than the first reproducing rate are recorded, wherein the first data and second data are recorded in separate areas on the disc. The disc is rotatable at a second reproducing rate. Responsive to a readout command, data is read out from a desired position on the disc, and output data is checked as to whether it is the first data or the second data. If the data is the first data, the output data is stored in the buffer memory unit at the second reproducing rate. On the other hand, the first data of the buffer memory unit is read out at a first reproducing rate, while the second data is accessed if the first data is not being read out from the disc. During reproduction of the combined disc, the disc can be reproduced at a multiple speed to enable the CD-DA data and the CD-ROM data to be read out time-divisionally in parallel.

Disc reproducing apparatus and method

A reference voltage generating circuit has a control transistor whose collector-emitter path is connected between the output terminal and an input terminal, first and second resistors connected in series with the collector-emitter path of a current detection transistor between the output terminal and ground with the base of the current detection transistor being connected to a connection point between the first and second resistors, a third transistor whose base-emitter path is connected in parallel to the collector-emitter path of the current detection transistor and which has an emitter periphery area n times an emitter periphery area of the current detection transistor, a fourth transistor of the same conductivity type as the current detection transistor and the base of which is connected to the base of the current detection transistor, and a circuit in which a difference between the collector currents of the third transistor and the fourth transistor is detected and a corresponding signal is negatively fed back to the base of the control transistor for ensuring that a constant reference voltage is provided at the output terminal.

Growing community of inventors

Kanagawa, Japan

Takeshi Hachimori