Apparatus for constant angular velocity reading of constant linear velocity disks
US5425014A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 1994 |
| Grant date | Jun 13, 1995 |
| Priority date | — |
| Expiry date | Apr 18, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2020/10981
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for reading at a constant angular velocity a CD-ROM or like optical disk that is designed to be driven at a constant linear velocity, thereby combining the higher storage capacity of CLV with the shorter access time of CAV. The CLV disk has clock data prerecorded all along its multiturn spiral track together with primary information to be retrieved and utilized by the user. As an optoelectric transducer traces the track, a first clock derives from the clock data a first clock signal which varies in frequency in step with the varying rate of the clock data being read on the CLV disk being driven at CAV. The recovered primary information is written on a memory being docked by the first clock signal and read out therefrom while the memory is being clocked by a second clock signal having a constant frequency, so that the information has a constant transfer rate on being read out from the memory. The information may be demodulated before or after being made constant in transfer rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.