VITERBI ACS UNIT WITH RENORMALIZATION

摘要

In a Viterbi decoder including an add-compare-select (ACS) processor (ACS0, ACS1,... ACS63), speed is enhanced without loss of performance by maintaining a dynamic cumulative metric range for computed metrics to obtain two computed metrics, and the smaller of the two computed metrics is stored along with previously computed state metrics. In the renormalization circuit (RENORM), the stored state metrics are compared with a selected scale factor, for example one-half maximum scale factor, and all current state metrics are rescaled when the minimum stored metric value exceeds the selected scale factor.