Real-time implementation of a wideband speech coder

SINTEF DELAB and Norwegian Telecom Research presented a speech compression algorithm at the lEEE Workshop on Speech Coding for Telecommunications in 1991 El]. The algorithm is for the coding of wideband (7 kHz) speech signals at 16 kbit/s using code excited linear prediction (CELP), primarily intended for use in audio-visual coding systems (e.g., videotelephony) in the ISDN network, or other telecommunication equipment using loudspeaker sound. The basic CELP encoder structure is illustrated in Figure 1. This paper describes the work performed on the speech coding algorithm since 1991, as well as a real-time implementation of one version of this coder on a single DSP.