Stability of fixed-point state-space digital filters using two’s complement arithmetic: Further insight

The purpose of this note is to point out that for the digital filters using two’s complement arithmetic, the criterion in (Singh, 2010) can be transformed into a simpler form; the stability criteria in Singh (2010) and Mills et al. (1978) are equivalent in some cases. A third-order example in which Singh’s criterion is satisfied and Mills–Mullis–Roberts criterion fails is presented.