A new framework for designing and analyzing BIST techniques and zero aliasing compression

A general framework for shift register-based signature analysis is presented, and a mathematical model for this framework-based on coding theory-is developed. There are two key features of this formulation, first, it allows for uniform treatment of LFSR, MISR, and multiple MISR-based signature analyzer. In addition, using this formulation, a new compression scheme for multiple output CUT is proposed. This scheme, referred to as multiinput LFSR, has the potential to achieve better aliasing than other schemes such as the multiple MISR scheme of comparable hardware complexity. Several results on aliasing are presented, and certain known results are shown to be direct consequences of the formulation. Also developed are error models that take into account the circuit topology and the effect of faults at the outputs. Using these models, exact closed-form expressions for aliasing probability are developed. A closed-form aliasing expression for MISR under an independent error model is provided.<
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