Study Of Cab Signal Data Lossless Compression MethodSecond GenerationWavelet Analysis

The signal waveform of locomotive reflects the working status of tract circuit, which provides the basis for locomotive signal fault diagnosis. Thus, the signal waveform of locomotive has a broad practical value. As the increment of train operation routes, cab-signaling recorder cannot record the signal waveform data of the whole train travelling process completely due to the limitation of storage capability and direct store mode. Therefore, it has been becoming more and more important to research on a lossless compression algorithm for waveform data using for the practical application of cab signal.This paper chooses ZPW-2000A track circuit and domestic frequency shift track circuit as research object. Based on wavelet theory and the analysis of the character of waveform data, the author presents a lossless compression for second-generation wavelet that is used for cab signal recorder, and designs the method for compressing and decompressing the waveform data. The main research aspects are as fellows:1. Presents the lossless compression algorithm for waveform data based on second-generation wavelet. First, use second-generation wavelet algorithm to analyze the waveform data.Second, adopt3/5lifting scheme and4th decomposition level after theoretical analysis and simulation. Third, according to the distribution of waveform signal energy, divide the frequency band and store the effective frequency band's second-generation wavelet coefficient. Forth, realize lossless compression of waveform data.2. Prove the correctness and affectivity. Test compressive property of the proposed compression algorithm based on the data from simulation. The test result shows that the proposed algorithm can get high compression ratio as well as lossless data information. Moreover, the proposed algorithm is easy to realize and has a wide practicability.3. Based on MATLAB GUI technology, design the general scheme for decompression software for cab signal recorder. This software can decompress the compressed signal waveform data from locomotive on-board signal equipment according to actual demand.