Design of Fast Self-Testing Checkers for a Class of Berger Codes

The Berger codes are optimal separable codes that detect all undirectional errors. In this correspondence a new procedure of designing self-testing checkers (STC´s) for codes with I information bits, where I = {2^K-2, 2^K-l} and I ≥ 3, is proposed. I ≥ 3. The new checker is basically composed of u = ⌈(I + 1)/2⌉ STC´s for m-out-of-n codes with n = I + 1 and m = 2p + 1, O ≤ p ≤ u -1. Simple STC for the codes with I = 2^K-1is also given. All new checkers can be implemented as inverter-free circuits and hence be self-testing for all unidirectional faults. Comparison to earlier designs reveals essential improvement in speed of operation.