Optical data storage system with differential data detection and source noise subtraction for use with magneto-optic, write-once and other optical media
US5537383A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1995 |
| Grant date | Jul 16, 1996 |
| Priority date | — |
| Expiry date | Mar 1, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10515
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for providing differential detection and source noise subtraction in data signals read from magneto-optic (MO), write-once (WO) or other types of optical storage media using an incident radiation beam. A source monitor signal is generated by detecting radiation from an optical source providing the radiation beam. An error detector generates an error signal corresponding to a difference between the source monitor signal and a reference signal. A power level of the radiation beam is adjusted in response to the error signal. A data signal generator is adapted to receive a return beam resulting from application of the radiation beam to the medium and to generate a WO data signal from the return beam. A signal combiner combines the data signal and the source monitor signal to provide a compensated WO data signal. An MO data signal may be generated using a separate AGC circuit to adjust the gain of each differential detection channel in accordance with low-frequency amplitude differences between the detected signals and a reference signal. The same reference signal may be used in both the source noise subtraction and the MO data signal generation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.