Bandwidth Efficient Mixed Pseudo Analogue - Digital Speech Transmission

Today’s speech coding and transmission systems are either analogue or digital, with a strong shift from analogue sys-tems to digital systems during the last decades. In this pa-per, both digital and analogue schemes are combined for the benefit of saving transmission bandwidth, complexity, and of improving the achievable speech quality at any given signal-to-noise ratio (SNR) on the channel. The combination is achieved by transmitting pseudo ana-logue samples of the unquantized residual signal of a lin-ear predictive digital filter. The new system, Mixed Pseudo Analogue-Digital (MAD) transmission, is applied to narrow-band speech as well as to wideband speech. MAD trans-mission over a channel modeled by additive white Gaussian noise (AWGN) is compared to the GSM Adaptive Multi-Rate speech codec mode 12.2 kbit/s (Enhanced Full-Rate Codec), which uses a comparable transmission bandwidth if channel coding is included. 1