This paper investigates the subjective effects of speech quality impairments resulting from cell loss and coding distortion, which are likely to occur in communications systems using ATM (Asynchronous Transfer Mode). A method is proposed for improving speech quality degraded by cell loss. This method uses an LPC (Linear Predictive Coding) spectrum-shaping filter. The performance of the proposed method is compared with that of a speech signal waveform substitution method. Listening tests were used to assess both quality (defined using a rating scale) and intelligibility. Speech quality evaluation results are presented for various speech coding methods, methods for dividing speech signals into cells, unit cell sizes, and missing-cell-rates. Experimental results show the robustness of embedded coding against cell loss and the effectiveness of the proposed quality-improvement method. Keywords: Speech quality evaluation; ATM; Cell loss
Bibliographic reference. Nagabuchi, Hiromi / Kitawaki, Nobuhiko (1991): "Evaluation and improvement of coded speech quality degraded by cell loss in ATM networks", In EUROSPEECH-1991, 603-606.