Phonetic classification on wide-band and telephone quality speech

Abstract

Benchmarking the performance for telephone-network-based speech recognition systems is hampered by two factors: lack of standardized databases for telephone network speech, and insufficient understanding of the impact of the telephone network on recognition systems. The N-TIMIT database was used in the experiments described in this paper in order to calibrate the effect of the telephone network on phonetic classification algorithms. Phonetic classification algorithms have been developed for wide-band and telephone quality speech, and were tested on subsets of the TIMIT and N-TIMIT databases. The classifier described in this paper provides accuracy of 75% on wide-band TIMIT data and 66.5% on telephone quality N-TIMIT data. Over-all the telephone network seems to increase the error rate by a factor of 1.3.