| 摘要 |
PURPOSE:To secure a stable and wide capture range by detecting the frequency of a recovered clock, and shifting the capture range of a clock extraction part in accordance with the detected frequency. CONSTITUTION:A data on a tape 603 is read out by heads 605a, 605b and supplied to a PLL part 616. The frequency of a clock recovered in the PLL 607 is detected by a detector part 608 and transmitted to a capture range control part 615. The control part 608, when a PLL frequency detection flag (d) from the detector part 608 is active, determines the value of a capture range control data (f) in accordance with a PLL frequency data (c)(701). The data (f) is transmitted to the PLL 607 and the center value 703 of its capture range 702 is determined. As a result, the virtual capture range realized by a PLL part 616 as a whole is extended by + or -8%.
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