Semi-static data compression/expansion method
US5323155A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1992 |
| Grant date | Jun 21, 1994 |
| Priority date | — |
| Expiry date | Dec 4, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M7/3088
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A method of transmitting compressed data using a Ziv-Lempel compression/expansion algorithm, using an adaptive Ziv-Lempel (AZL) dictionary modified to a mature state. The mature state is signaled by a time to freeze signal sent as a switch-over signal from a transmitting location to each receiving location. These signals freeze and synchronize the AZL dictionaries at both locations, and starts a translation of the frozen AZL dictionary to a static SZL dictionary--at least at the transmitting location. The SZL dictionary is then used to compress records being transmitted. An index translation process is generates translation information to allow the receiving locations to decompress SZL indices into original characters. The AZL-to-SZL dictionary translation process re-organizes the frozen AZL to an SZL dictionary. The SZL process is used until either the end of the inputted sequence, or a time to unfreeze signal is generated. An SZL to AZL switch-over signal is generated in response to the time to unfreeze signal, which in turn signals a switch over back to the AZL process and invokes the saved frozen AZL dictionary to be used to until mature to on the current input data stream at w…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.