Abstract: Speech is one of the natural ways of communication amongst humans. Nowadays there is insatiable demand for speech communication as it carries more information like speaker identity, emotional state, prosodic nuance which adds naturalness in communication. With rapid growth and increased number of applications there exists a need for devising an approach for data compression techniques which reduces communication cost by using available bandwidth and storage space effectively. The speech coding techniques helps to achieve lower bit rate by simultaneously maintaining the original speech quality.This paper aims at implementing the CELP (Code Excited Linear Prediction) and MELP (Mixed Excitation Linear Prediction) coding techniques of speech using MATLAB R2009a. These coding techniques are analyzed on the basis of subjective and objective tests like Mean Square Error (MSE), Mean Opinion Score (MOS) and Signal-to-Noise Ratio (SNR). The analysis of CELP speech coding technique shows that this technique is an improvement to a coder called Linear Predictive Coder (LPC). It is an efficient coding technique having bit rate in the range 9.6 kbps to 16 kbps. The analysis of MELP coding technique shows that this coder removes the voicing error in two state excitation model of LPC. It is a low bit rate coder having a bit rate of 2.4 kbps and mainly used by military and Federal Standards. The comparative results of different values which are obtained for CELP and MELP coding techniques give a clear idea about more efficient coding technique.
Keywords: Speech coding, Linear Prediction (LP), CELP (Code Excited Linear Prediction), MELP (Mixed Excitation Linear Prediction)