METHOD FOR COMPRESSING QUASISTATIC DATA AND EXPANDING THE SAME

摘要

PURPOSE: To reduce the computer throughput for data transmission in a transmission area and a reception area and to improve the data transmission rate. CONSTITUTION: A signal for switching between an adaptive Ziv-Lempel(AZL) process and a static Ziv-Lempel(SZL) process is generated corresponding to the generation of a freezing signal, inserted into a record and compressed, and transmitted to reception areas. In each reception area, the switching signal for generating an AZL dictionary from received compressed records and freezing a current AZL dictionary is used and it is used as an SZL dictionary (The SZL dictionary is not corrected unlike the AZL dictionary at this time). A process for selective substitution from the AZL to the SZL dictionary is used to restructure a frozen AZL dictionary (after copy storage) as the SZL dictionary. An SZL process is carried on until input sequential data end or a defreezing signal is generated. The signal for switching from SZL to AZL is generated according to the defreezing signal for switchback to the AZL process. In this case, the stored frozen AZL dictionary is reused.