IMPLEMENTITION OF SPEECH CODING USING VOICE EXCITED LILNEAR PREDICTIVE VOCODER

Abstract

The focus of the project entitled “IMPLEMENTATION OF SPEECH CODING USING VOICE EXCITED LINEAR PREDICTIVE VOCODER” is to ultimately to reduce the bit rate to 16 kbits/sec. so that speech quality is less synthetic and much easier to understand. The main idea behind the voice-excitation is to avoid the imprecise detection of the pitch and the use of an impulse train while synthesizing the speech. One should rather try to come up with a better estimate of the excitation signal. Thus the input speech signal in each frame is filtered with the estimated transfer function of LPC analyzer. This filtered signal is called the residual. If this signal is transmitted to the receiver, one can achieve a very good quality. The tradeoff, however, is paid by a higher bit rate, although there is no longer a need to transfer the pitch frequency and the voiced / unvoiced information. We therefore looked for a solution to reduce the bit rate to 16 kbits/sec. A voice excited LPC vocoder, sends LP parameter...