SPEECH CODING WITH LINEAR PREDICTIVE CODING

Abstract

Speech coding has been and still is a major issue in the area of digital speech processing in which speech compression is needed for storing digital voice and it requires fixed amount of available memory and compression makes it possible to store longer messages. Several techniques of speech coding such as Linear Predictive Coding (LPC), Waveform Coding and Sub band Coding exist. In this paper we proposed a technique called LPC. This is used to characterize the vocal track and inverse filter is used to describe the vocal source and therefore it is used as the input for the coding. The speech coder that will be developed is going to be analyzed using both subjective and objective analysis. Subjective analysis will consist of listening to the encoded speech signal and making judgments on its quality. The quality of the played back speech will be solely based on the opinion of the listener. The speech can possibly be rated by the listener either impossible to understand, intelligible or natural sounding. Even though this is a valid measure of quality, an objective analysis will be introduced to technically assess the speech quality and to minimize human bias. The objective analysis will be performed by computing Segmental Signal to Noise Ratio (SEGSNR) between the original and the coded speech signal.