Design Of Real-time Lossless Compression System Based On FPGA

Some dynamic measuring system in complex environment has characteristic of high measurement accuracy, large volume of data, far transmission distance and slow speed of wireless transmission. That cause great difficulties in data storage and transmission. So implementation of hardware circuit for real-time lossless compression has become necessary.This thesis mainly deals with the design and implementation of a real-time lossless data compression system. The compression algorithm is LZW algorithm. First of all, through the analysis of commonly used lossless data compression algorithm to draw a conclusion: LZW algorithm has good characteristics in real-time, implementation complexity, the required storage capacity, compression algorithm performance and the application of occasions. Therefore this design uses it as the hardware implementation algorithm. The real-time lossless compression system consists of hardware for real-time lossless compression, testing software, decompression software and reading software. The hardware circuit for real-time lossless compression includes data acquisition, data compression, control circuit, data storage, power management, and so on. The core device is ALTERA FPGA EP2C5T144I8. FPGA will not only achieve real-time lossless LZW compression algorithm, is also responsible for the completion of ADC, Flash memory control functions. The input buffer and the dictionary memory are constructed based on the FPGA's internal RAM resources and the strategy of maintaining dictionary is conductive to hardware implementation. This design uses QUARTUS II for the software development platform, VHDL + schematic diagram as the hierarchical input description.Hardware real-time lossless compression circuit based on FPGA is designed and realized. The corresponding testing software and decompression software are also designed by using VC. The testing software provides a great convenience for upgrading hardware. Simulation and experiment results show that real-time compression rate achieves 1M data samples per second and each sample is of 12bit. The data compression ratio is generally about 25% in a great measure with 1G bit storage capacity, be able to meet the real-time requirements of some systems.