Circuit for measuring parameter of time-base error of pulse train, and optical disk recording apparatus
US7009924B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 1, 2001 |
| Grant date | Mar 7, 2006 |
| Priority date | — |
| Expiry date | Apr 21, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/2562
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A PLL circuit (24) reproduces a clock signal from a reproduction EFM signal of an optical disk (10). A phase error signal (pco) of the PLL circuit (24) is converted into an absolute value by an absolute value circuit (38), and is averaged for each subcode frame period by an accumulator (40). The recording beam power of a laser beam is determined on the basis of an output of the accumulator (40). A pulse-length discrimination circuit (26) discriminates the pulse length of the reproduction EFM signal. A specific-pulse-length phase-error-signal extracting circuit (42) extracts the phase error signal (pco) of a specific pulse length. The extracted phase error signals (pco) are averaged for the respective subcode frame periods by a accumulator (44). The time base of the corresponding pulse length of the recording EFM signal is corrected on the basis of the output of the accumulator (44).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.