| 摘要 |
A servo control loop for a disc player initially sets an offset value, which is used throughout search and playback to control the gain of an equalizer in the servo loop. The offset value is determined by first moving a pickup head to radially central position of the disc and reading the time code address data recorded at that position. The read address is compared with a calculated, expected address to determine if the two are within a given distance. If they are, the offset is set as a predetermined value, e.g., zero. If they are not within a given distance, the offset is determined one of two ways. Either the difference is used as the offset, or the pickup head is moved to the innermost circumference of the data portion of the disc and the address data read therefrom is used as the offset. During search and playback the offset is subtracted from the continuously read address data, and the difference controls the gain of the equalizer.
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