Effects of speech coding on text-dependent speaker recognition

The introduction of speech coding systems in the telephone network raises the question of their impact on formant frequencies, fundamental frequency trajectories and other acoustics features used for text dependent speaker identification. This paper presents results of the investigation of three common speech coding systems (CELP, LPC and GSM) on the pitch and formant frequencies of speech extracted from several dialect regions of the TIMIT Speech Corpus. Voice pitch (F0) and formant frequencies (F1, F2, F3) extracted from time aligned, uncoded and coded speech samples are compared to establish the statistical distribution of error attributed to the coding system.