PatentDOI
Hybrid switched multi-pulse/stochastic speech coding technique
TLDR
In this paper, an unvoiced speech performance was improved in low-rate multi-pulse coders by employing a simple architecture with an output quality comparable to code excited linear predictive (CELP) coding.Abstract:
Improved unvoiced speech performance in low-rate multi-pulse coders is achieved by employing a multi-pulse architecture that is simple in implementation but with an output quality comparable to code excited linear predictive (CELP) coding. A hybrid architecture is provided in which a stochastic excitation model that is used during unvoiced speech is also capable of modeling voiced speech by use of random codebook excitation. A modified method for calculating the gain during stochastic excitation is also provided.read more
Citations
More filters
PatentDOI
Variable rate vocoder
Jacobs Paul E,Gardner William R,Lee Chong U,Gilhousen Klein S,Lam S Katherine,Ming-Chang Tsai +5 more
TL;DR: In this paper, a variable rate coding of frames of digitized speech samples is proposed, comprising the steps of determining a level of speech activity for a frame of digitised speech samples, selecting an encoding rate from a set of rates based upon the determined level of activity within said frame, and coding said frame according to a predetermined coding format for said selected rate wherein each rate has a corresponding different coding format.
Patent
Method and apparatus for performing speech frame encoding mode selection in a variable rate encoding system
TL;DR: In this paper, the authors proposed a method for dynamically adjusting the average output data rate of the speech coder with minimal impact on the quality of the input speech, which can be applied to both unvoiced speech and temporally masked speech.
PatentDOI
Analysis-by-synthesis 2,4 kbps linear predictive speech codec
TL;DR: In this article, a linear predictive speech codec is proposed, which includes a spectrum synthesizer for providing reconstructed speech generation in response to excitation signals; a distortion analyzer for comparing the reconstructed speech with an original speech, and providing a distortion analysis signal in response of such comparison.
Patent
Excitation vector generator, speech coder and speech decoder
TL;DR: In this paper, a random code vector reading section was replaced with an oscillator for outputting different vector streams in accordance with values of input seeds, and a seed storage section for storing a plurality of seeds.
Patent
Comfort noise generation for digital communication systems
TL;DR: In this paper, a digital discontinuous cellular communication system has a transmitter that transmits two frames of data following detection of voice inactivity, and a receiver includes a comfort noise generator that uses the two frames to output noise to the speaker during period of voice activity.
References
More filters
Proceedings ArticleDOI
Code-excited linear prediction(CELP): High-quality speech at very low bit rates
Manfred R. Schroeder,B. S. Atal +1 more
TL;DR: A code-excited linear predictive coder in which the optimum innovation sequence is selected from a code book of stored sequences to optimize a given fidelity criterion, indicating that a random code book has a slight speech quality advantage at low bit rates.
Proceedings ArticleDOI
A new model of LPC excitation for producing natural-sounding speech at low bit rates
TL;DR: This paper describes a new approach to the excitation problem that does not require a priori knowledge of either the voiced-unvoiced decision or the pitch period, and minimizes a perceptual-distance metric representing subjectively-important differences between the waveforms of the original and the synthetic speech signals.
Journal ArticleDOI
A pattern recognition approach to voiced-unvoiced-silence classification with applications to speech recognition
TL;DR: A pattern recognition approach for deciding whether a given segment of a speech signal should be classified as voiced speech, unvoiced speech, or silence, based on measurements made on the signal, which has been found to provide reliable classification with speech segments as short as 10 ms.
Journal ArticleDOI
Amplitude optimization and pitch prediction in multipulse coders
Sharad Singhal,B. S. Atal +1 more
TL;DR: The algorithm provides a framework for computing multipulse excitation with varying degrees of optimization and computational complexity and finds that speech quality depends on the pulse rate and female speech requires a higher pulse rate than male speech.
Proceedings ArticleDOI
Strategies for improving the performance of CELP coders at low bit rates (speech analysis)
TL;DR: It is found that the coder does not reproduce high frequencies well and that rapid changes in the speech signal are not adequately tracked.