Eyes free dialing for cellular telephones

This paper describes a chip set, the DSPG5006, that implements digital signal processing algorithms for voice dialing in cellular telephones. The problem of achieving high performance speech recognition in noisy car cabins is addressed by using noise immune techniques for preprocessing, feature extraction, template training and template comparison. The chip set supports an isolated word, speaker dependent, speech recognition system built around a modified dynamic time warping algorithm. A speech specific voice activated switch is used in conjunction with a simplified endpoint detector. A two-stage training mode permits building of compact and reliable templates that are compared with incoming words in the recognition mode. Recognition rates are greater than 98% in car cabins, and over 99% in the laboratory. The chip set can be configured to support speech synthesis, so that the user is guided in a friendly manner throughout the use of the system for both prompting and verification