Spindle servo circuit in high-speed optical disk reproducer
US5748587A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 15, 1996 |
| Grant date | May 5, 1998 |
| Priority date | — |
| Expiry date | Jul 15, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0037
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A spindle servo circuit in an optical disc reproducing apparatus operates with enhanced stability at disc rotation speeds substantially higher than normal. The spindle servo circuit includes a first phase comparator which compares the phases of a reference clock signal and a reproduced frame clock signal and outputs a phase difference signal. The spindle servo circuit also includes a first low pass filter for generating a revolution speed control signal for a spindle motor by low-pass filtering the phase difference signal. The revolution speed control signal is input to a motor driving means for driving revolution of a spindle motor, which in turn spins the optical disc. Optical signals are picked up off the disc and run through a high frequency amplifier for amplifying and wave-shaping to produce a reproduction data signal. A phase locked loop circuit generates a reproduced bit clock signal from the reproduced data signal during normal operation, and during high speed operation (above a predetermined speed) generates the reproduced bit clock signal corresponding to a previous state. Thereby, in the spindle servo control system for operating at higher than normal speed, according t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.