A low-power, fixed-point, front-end feature extraction for a distributed speech recognition system

This work describes the optimization of a signal processing front-end for a distributed speech recognition system with the goal of reducing power consumption. Two categories of source code optimizations were used, architectural and algorithmic. Architectural optimizations reduce the power consumption for a particular system, in this case, the HP Labs Smartbadge IV prototype portable system. Algorithmic optimizations are more general and involve changes in the algorithmic implementation of the source code to run faster and consume less power. A cycle accurate energy simulation shows a reduction in power usage by 83.5% with these optimizations. The optimized source code runs 34 times faster than the original code, therefore it can run at lower processor clock speeds and voltages for further reductions in power consumption. This technique, known as dynamic voltage scaling, was implemented on the Smartbadge IV hardware for an overall reduction in power usage of 89.2%.