Sliding window data compression using a toroidal bit shift register
US5612693A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 14, 1994 |
| Grant date | Mar 18, 1997 |
| Priority date | — |
| Expiry date | Dec 14, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/3086
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
Systems and methods for compressing data. Lempel-Ziv data compression is applied in the context of an exhaustive sliding window implementation using a large character history bit pattern memory. Shifted updating of the character history bit pattern memory is accomplished through a pointer system. Linear patterns of bits, derived by COPY function from the character history bit pattern memory or by bit wise AND logic combination of selected bit patterns, are circularly shifted in synchronism with new data characters using a toroidal bit shift register. The relatively long bit strings subject to shifting are converted to a matrix format, shifted with fewer affected bits and returned to a linear format. The systems and methods materially improve the speed of exhaustive sliding window data compression as accomplished by general purpose processors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.