Introduction to A Fast and Low Bit rate Speech Coding Algorithm Pulse Position Linear Predictive Coding Project:

This paper discussed about a robust algorithm which provides quality speech less algorithmic complexity and at low bit rates. From the implementation point of view, high quality speech at low bit rate always come with the huge algorithmic complexities. There is a need to develop robust low rate coders which can accommodate signals other than speech. Current research is focused upon achieving high quality speech at low information rates. 

Overview: 

Vocoders works at low rates but also capable to produce synthetic quality speech.  Vocoders works based on making vocal tract as a simple tube as with an excitation source at one end.As the algorithms used in this thesis are of lower complexity, the codec delay is also very less.  The new algorithm proposed here is compared with the other existing algorithms on basis of voice quality, performance and voice intelligibility. 

A common man always expects a modern communication should takes place with high quality at low rates. Low cost VoIP devices can achieve this goal, and these are developed with a fast and low complexity voice codec. The algorithm proposed in this paper provides high speech quality and intelligibility at low bit rate and low algorithmic complexity.  Mean opinion scores and informal listening tests are used to verify the quality of these developed coders. 

Conclusions: 

Researches have been takes place to develop new speech coders which can able to produce high quality speech at low data rates.  Excitation signal is the main factor which affects natural sounding speech synthesis.  This paper discussed about the new parametric representation of an excitation signal and also designs a vocoder depends on the new excitation signal. When we placed pulses at peaks and residue signal valleys then the new excitation signal will created. The new vocoder which designed based on new excitation signal provides good quality at low bit-rate and codec delay.

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