Closed form aliasing probability for Q-ary symmetric errors

In built-in self-test schemes multiple-input signature registers (MISRs) are often used to compact test data. The error escape probability during compaction determines the quality of the compactor. The authors derive closed-form expressions for exact aliasing probability under the Q-ary error model for a large class of MISRs. It is shown that for Q-ary symmetric errors, the circuit complexity and propagation delay can be minimized by using a set of m single-bit linear feedback shift registers without increasing the aliasing probability. This also leads to a regular register structure