Abstract
Fault detection techniques using data compression methods have evolved during the last few years. Considerable work using individual Walsh spectral coefficients has been reported. In this paper, the application of spectral methods in testing of digital circuits with the emphasis on their usage for both input and output test compaction of digital circuits is described. Two closely related testing methods are discussed: syndrome testing and spectral testing as well as an overview of syndrome-testing and syndrome-testable design is presented. The necessary background and notation on Walsh spectral coefficients as well as their meaning in classical logic terms is shown.