A Pseudo-Random Transform Decomposition Method for Improving the Coding Compression Ratio of Test Data

To improve the coding compression ratio of test data, this paper proposes a pseudo-random transform decomposition method for preprocessing test data. The method decomposes the test set (composed of test data) into a primary component set (PCS) and a residual component set (RCS) by a pseudo-random transform, and they are the same size as the decomposed test set. The RCS is easier to encode and store in the automatic test equipment than the original test set, while the PCS is compressed using on-chip linear feedback shift register coding. Experimental results show that the total average compression ratio using code-based schemes can be improved by 13.34%, and the average compression ratio of variable length input Huffman coding is as high as 78.08%. During testing, the on-chip test pattern generator that restores the original test patterns of the test set has the characteristics of a simple structure and affordable hardware overhead.