Information disc recorder/reproducer and method for controlling recording/reproducing speed

Abstract

Information about the number of traversed tracks is acquired with a code at a first rotational speed and a second rotational speed in each area provided by dividing one rotation into m (m is a natural number equal to or larger than 1). As to the information about the number of traversed tracks, a difference is calculated between the areas. A value proportionate to the sum of absolute values of the information about the traversed tracks in the areas is used as a vibration detection value proportionate to vibration amplitude.

Description

Technical field [0001] The present invention relates to an information disc recording and reproducing apparatus and a recording and reproducing speed control method for an information disc recording and reproducing apparatus and a recording and reproducing speed control method thereof for preventing adverse effects caused by vibration caused by the mass eccentricity of the information recording medium. Background technique [0002] In recent years, the recording and reproducing speed in optical disc reproducing devices has increased significantly. This increase in recording and reproducing speed is achieved by increasing the rotation speed of the optical disc. [0003] However, as the rotation speed of the optical disk increases, the vibration caused by the eccentricity of the optical disk will adversely affect the control of the servo mechanism and the like. The problem is that the user of the optical disk reproducing apparatus has a very unpleasant feeling. [0004] In order to...

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Problems solved by technology

[0032] However, in the conventional optical disk reproducing apparatus disclosed in the above-mentioned Japanese Unexamined Patent Publication No. 2000-113581, since the track count result of the eccentric component measured at the first rotational speed is subtracted by calculation after the track count result at the second rotational speed is measured, Afterwards, complex calculations are required to obtain the vibration detection value equivalent to the vibration amplitude. Therefore, the value proportional to the square of the vibration amplitude is usually used as the vibration detection value. Accurately control the recording and playback speed, the problem is that the variables used in the calculation must use high-precision (more significant digits) data

[0033] In addition, multiplication is used too much, the calculation is complicated, and the number of steps of the control program increases, so there is a problem that the calculation time of the vibration detection value is prolonged, the calculation result is slow, and high-speed recording and reproduction speed control cannot be performed.

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