| 摘要 |
<p>PURPOSE:To eliminate the necessity of a plurality of times of envelope-level detections performed at respective tracking phase steps by a method wherein curve regression calculation is applied to the tracking phase and the characteristic curve of the envelope-level of reproducing signals. CONSTITUTION:Curve regression calculation is performed in a curve regression calculator 115 by using 256 data pairs (Xi, Yi) (wherein (i) denotes an integer not larger than 256) which are inputted from a data extractor 119. At that time, it is assumed that a tracking phase X and a reproducing signal Y approximately satisfy an equation (I):Y=aX<2>+bX+c. Under this assumption, the coefficients (a), (b) and (c) of the quadratic equation (I) are so determined as to have the equation (I) most closely agree with the characteristics of the actual measured data (Xi, Yi). With this constitution, even if the required time of a tracking operation for a conventional apparatus is short, or if the head width of a rotary head which is used for reproducing is different from the track width of a helical track, an optimum tracking phase can be determined uniquely and with a high accuracy.</p> |
