Proceedings ArticleDOI
A study on short-time phase and multipulse LPC
Isabel Trancoso,R. Garcia-Gomez,José Tribolet +2 more
- Vol. 9, pp 392-395
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TLDR
This study was prompted by direct observation of the structure of the excitation, where patterns of pulses may be found which are associated with phase-correcting mechanisms of the LPC impulse response, and developed a new multipulse technique based on a special ARMA model formed by cascading an all-pole with anall-pass network.Abstract:
Multipulse LPC, as is often designated the model proposed by Atal and Remae, has been directed towards 9.6 kb/s speech coding. However, at such bit rate, the speech quality is not yet generally acceptable. This paper has a double purpose - one is to investigate the role of short-time phase in multipulse LPC. The other is to look for different modelling structures to be used with this method. This study was prompted by direct observation of the structure of the excitation, where patterns of pulses may be found which are associated with phase-correcting mechanisms of the LPC impulse response. Consequently, a new multipulse technique was developed, based on a special ARMA model formed by cascading an all-pole with an all-pass network. This new model will be referred to as the MAPAP (Multipulse All-Pole All-Pass) method. Another one was tried in which the synthetic speech is formed by combination of several MAPAP signals. We therefore denoted it "multichannel multipulse" method. The potential advantages of both single and multichannel models seem rather promising.read more
Citations
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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
Efficient representation of short-time phase based on group delay
TL;DR: An efficient representation of short-time phase characteristics of speech sounds is proposed, based on findings which suggest the perceptual importance of phase characteristics, and it alleviates the voiced/unvoiced decision.
Proceedings ArticleDOI
Speech coding using waveform matching based on LPC residual phase equalization
TL;DR: A speech analysis-synthesis method based on linear predictive coding (LPC) residual phase equalization is presented for low-bit- rate natural sounding speech coding and a speech coder designed for bit rates lower than 4.8 kb/s is discussed.
PatentDOI
Multipulse excited pole-zero filtering approach for noise reduction
A-Chuan Hsueh,Chiu-Kuang Chuang +1 more
TL;DR: In this paper, an inverse LPC analysis of a frame of voiced speech is used to estimate a pulse train of primary pulses and a pole-zero filter is estimated to produce a synthesized speech signal.
Proceedings ArticleDOI
Pole-zero multipulse speech representation using harmonic modelling in the frequency domain
TL;DR: The conclusion is drawn that pole-zero filters actually are good candidates for a more efficient multipulse representation of voiced speech.
References
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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
How to make an all-pass filter with a desired impulse response
TL;DR: In this paper, it was shown that for any sequence of n + 1 numbers, an all-pass filter of order ≤ n can be constructed whose impulse response begins with the given sequence up to a gain factor.