Digital optical sound system
US5271021A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1991 |
| Grant date | Dec 14, 1993 |
| Priority date | — |
| Expiry date | Dec 13, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/87
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Estimates of the horizontal and vertical positions of digital bits on film are corrected by tracking the bit transition boundaries in the horizontal and vertical directions. Frequency of useful film bit transitions in the vertical direction is maximized prior to recording by error correction encoding the digital audio bytes using a symmetrical generator polynomial and then selectively inverting symmetric portions of each codeword. Frequency of useful film bit transistions in the horizontal direction is maximized prior to recording by channel encoding the error correction symbols in each codeword so as to force the weight of the resulting symbol to be half the number of data bits per symbol.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.