Partial response coding for a multi-level optical recording channel
US5537382A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 22, 1994 |
| Grant date | Jul 16, 1996 |
| Priority date | — |
| Expiry date | Nov 22, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/013
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system and method for recording multi-level data to a multi-amplitude recording channel encodes binary data to form multi-level data. The multi-level data are recorded to the storage media for later recall. The system utilizes linear, multi-amplitude recording media which allows data to be stored as multi-level data--requiring fewer `bits` to represent the same number of symbols. To obtain greater data density in the storage media, a diffraction limited write laser is utilized, resulting in a smaller write-spot size. Because the read laser is of a longer wavelength, its diffraction limited spot size is larger. As a result, more than one mark is read at a given read time resulting in a inter-symbol interference. Trellis coded modultation techniques are adopted to convert the binary input data into M-ary data having M levels. Further coding is then performed to compensate for the effects of the inter-symbol interference. This is accomplished by precoding the data using a Tomlinson-Harashima precoder. The precoding results in multi-level data (of m levels, where m.ltoreq..infin.).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.