A low-power integrated circuit for remote speech recognition

In this paper, a low-power, low-voltage speech processing system is presented. The system is intended to be used in remote speech recognition applications where feature extraction is performed on terminal and high-complexity recognition tasks are moved to a remote server accessed through a radio link. The proposed system is based on a CMOS feature extraction chip for speech recognition that computes 15 cepstrum parameters, each 8 ms, and dissipates 30 mu W at 0.9-V supply. Single-cell battery operation is achieved. Processing relies on a novel feature extraction algorithm using 1-bit A/D conversion of the input speech signal. The chip has been implemented as a gate array in a standard 0.5-mu m, three-metal CMOS technology. The average energy required to process a single word of the TI46 speech corpus is 10 mu J. It achieves recognition rates over 98% in isolated-word speech recognition tasks.