基于信号周期相似性和LZW编码的数据压缩方法

摘要

Ideal power quality signal takes the form of standard sine wave and are periodically repeated. Although the actual signal may contain distortions, the sampled data in each period still has strong similarities. Based on the feature, a single yet effective data compression method is presented. First, the sampled data in a period is selected as the basic signal. Then it is subtracted with the data in other periods, and the result is saved. The result value less than the threshold is then set to zero. Finally, the data compression algorithm with LZW encoding is presented. Different power quality signals are simulated with Matlab, and the simulation results show that the proposed method is effective and simple with good compression performance.%理想的电能质量信号呈现标准的正弦波形，具有周期性重复的特点。实际的信号虽然可能会出现各种电能质量现象。但是，在各个周期时间内的采样数据仍然具有很强的相似性。根据电能质量信号的这一特点，可以提出一种简单有效的数据压缩方法。首先提取某一个周期时间内的采样数据作为基准，然后将其他周期时间内的数据与该基准作减法处理，保存差值。对差值采取相应的阈值处理，将较小的数值置零，最终结合LZW编码方法实现数据压缩。文中详细地介绍了算法的实现过程和LZW编码的工作原理。利用Matlab平台模拟了几种不同的电能质量现象，进行算法仿真。经验证，该方法实现简单，处理速度快，并且可以取得较好的压缩效果。