Rotational velocity controlling system for information recording medium

Abstract

A rotational speed control device for an information recording medium, simultaneously using the linear velocity information of the recording and reproduction position on an optical disc (102) obtained by a synchronous signal cycle counter (107) and the optical disc (102) obtained by a FG cycle counter (109) ), the control information generation circuit (200) generates a rotation control information and gives it to the motor drive circuit (103). In addition, the variation detection circuit (114) generates a linear velocity abnormality detection signal for an abnormality detected from the output signal of the dividing circuit (110), and turns off the switch (115) to prevent abnormal operation of the spindle motor (101). It is possible to smoothly switch modes between CAV and CLV control using one rotation control information during continuous recording and reproduction operations on an optical disc or the like. In addition, disturbance of CLV control due to flaws on the information recording medium can be reduced.

Description

technical field [0001] The present invention relates to a rotation speed control device in an information recording and reproducing device for recording and reproducing information on information recording media such as CD (Compact Disc) and CD-R / RW (Compact Disc Recordable / Rewritable). Background technique [0002] In optical disks such as CDs, in order to increase the information recording capacity, the physical format of information recording is defined as the CLV (Constant Liner Velocity, constant linear velocity) method. [0003] In order to record and reproduce these optical disks at a constant linear velocity (hereinafter referred to as "CLV recording and reproduction"), it is necessary to change the rotational speed of the optical disk according to the physical radial position of recording and reproduction. That is, it is necessary to set the rotational speed at a position with a radius of 25 mm to twice the rotational speed at a position with a radius of 50 mm. In ...

AI Technical Summary

Problems solved by technology

[0011] However, in the above-mentioned CLV recording and reproducing method, since the rotation control information is obtained from the recording information on the information recording medium, there is the following problem: when there is a defect such as a flaw on the recording medium, it cannot be accurately rotated. Get rotation control information

In the device that implements the mode switching of rotation control, it is inevitable that the rotation speed of the recording medium will be disturbed at the moment when the rotation mode is switched, so it is difficult to smoothly record the entire recording surface of the optical disc at one time.

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