Constrained-stochastic-excitation coding

Details Constrained-stochastic-excitation coding Constrained-stochastic-excitation coding

1996-10-07

1998-02-17

MacDonald, Allen R.

395 273, G10L 900

Patent

active

057199922

ABSTRACT:
In CELP coding, stochastic (noise-like) excitation is used in exciting a cascade of long-term and short-term all-pole linear synthesis filters. This approach is based on the observation that the ideal excitation, obtained by inverse-filtering the speech signal, can be modeled for simplicity as Gaussian white noise. Although such stochastic excitation resembles the ideal excitation in its global statistical properties, it contains a noisy component that is irrelevant to the synthesis process. This component introduces some roughness and noisiness in the synthesized speech. The present invention reduces this effect by adaptively controlling the level of the stochastic excitation. The proposed control mechanism links the stochastic excitation to the long-term predictor in such a way that the excitation level is inversely related to the efficiency of the predictor. As a result, during voiced sounds, the excitation level is considerably attenuated and the synthesis is mainly accomplished by exciting the short-term filter with the periodic output of the long-term filter. This reduces the noisiness, enhances the pitch structure of the synthesized speech and its perceptual quality.

REFERENCES:
patent: 4797926 (1989-01-01), Bronson et al.
patent: 4827517 (1989-05-01), Atal et al.
patent: 4868867 (1989-09-01), Davidson et al.
patent: 4899385 (1990-02-01), Ketchum et al.
patent: 5481642 (1996-01-01), Shoham

Affiliated with

Also associated with

Rating

Constrained-stochastic-excitation coding does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Constrained-stochastic-excitation coding, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Constrained-stochastic-excitation coding will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1790859