COMPACT: a hybrid method for compressing test data

The overall throughput of automatic test equipment (ATE) is sensitive to the download time of test data. An effective approach to the reduction of the download time is to compress test data before the download. The authors introduced a test data compression method which outperforms other methods for compressing test data. Our previous method was based on the Burrows-Wheeler transformation on the sequence of test patterns and run-length coding. In this paper, we present a new method, called COMPACT, which further improves our previous method. The key idea of COMPACT is to employ two data compression schemes, run-length coding for data with low activity and GZIP for data with high activity. COMPACT increases the compression ratio of test data, on average, by 1.9 times compared with our previous method.