Analysis and Evaluation of Speech PCM and Differential Pcm Systems Using Various Logarithmic and Exponential Quantizers

摘要

The report presents a theoretical analysis and computer simulations of differential PCM and PCM systems used for speech signals. The simulations were performed in real time on an Adage AGT-10 hybrid computer using a speech sentence as input. The quantizers used were either logarithmic or exponential. The performance of the systems with varying amounts of companding were compared. The performance metric used in theoretical derivations and in the computer simulations is the signal to quantizing noise power ratio. Three, four, five, and six bit PCM and differential PCM systems were simulated and compared. Logarithmic quantizers with low-mu were found to be superior to exponential quantizers. At any given bit rate differential PCM was superior to PCM. (Author)