Patent
Low-delay code-excited linear-predictive coding of wideband speech at 32kbits/sec
Erik Ordentlich,Yair Shoham +1 more
TLDR
In this article, a CELP code/decoder based system is improved for use with a wide-band signal such as a high-quality speech signal by modifying the noise weighting filter used in such systems to include a filter section which affects primarily the spectral tilt of the weighting filters in addition to a filter component reflecting formant frequency information in the input signal.Abstract:
An improved digital communication system, e.g., a CELP code/decoder based system, is improved for use with a wide-band signal such as a high-quality speech signal by modifying the noise weighting filter used in such systems to include a filter section which affects primarily the spectral tilt of the weighting filter in addition to a filter component reflecting formant frequency information in the input signal. Alternatively, the weighting is modified to reflect perceptual transform techniques.read more
Citations
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Patent
Audio decoding device and compensation frame generation method
TL;DR: In this article, an audio decoding device capable of improving audio quality of a decoded signal by considering the energy change of a past signal in loss compensation processing was proposed, where an energy change calculation unit (143) calculates an average energy of an audio source signal of one-pitch cycle from the end of the ACB vector outputted from an adaptive codebook (106).
Patent
Method and apparatus for adjusting a spectrum shape of a speech signal
TL;DR: In this paper, a first filter with pole-zero transfer function A(z)/B(z) for subjecting a speech signal to a spectrum envelop emphasis and a second filter cascade-connected with the first filter, independently deriving two filter coefficients used in the second filter for compensating for the spectral tilt from the pole zero transfer function.
Patent
Formant emphasis method and formant emphasis filter device
TL;DR: In this article, a spectrum emphasis filter was proposed for emphasizing the formant as the spectral peak of an input speech signal and attenuating the spectral valley of a speech signal, and a first-order variable characteristic filter whose characteristic adaptively changes in accordance with the characteristic of the input signal was used to compensate a spectral tilt included in an output signal from the spectrum emphasis filtering.
PatentDOI
Speech synthesizer having an acoustic element database
TL;DR: In this paper, a tolerance region is identified based on a concentration of trajectories that correspond to different phoneme sequences, and the acoustic elements for the database are formed from portions of the phonetic sequences by identifying cut points (250) in the phonetics sequences which corespond to time points along the respective trajectories proximate the tolerance region.
Patent
Perceptual weighting device and method for efficient coding of wideband signals
TL;DR: In this article, a perceptual weighting device for producing a perceptually weighted signal in response to a wideband signal comprises a signal preemphasis filter, a synthesis filter claculator, and a perceptual weighted filter.
References
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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.
Journal ArticleDOI
Transform coding of audio signals using perceptual noise criteria
TL;DR: A 4-b/sample transform coder is designed using a psychoacoustically derived noise-making threshold that is based on the short-term spectrum of the signal, and tested in a formal subjective test involving a wide selection of monophonic audio inputs.
Journal ArticleDOI
Predictive coding of speech signals and subjective error criteria
TL;DR: Improved speech quality is obtained by efficient removal of formant and pitch-related redundant structure of speech before quantizing, and by effective masking of the quantizer noise by the speech signal.
Journal ArticleDOI
A class of analysis-by-synthesis predictive coders for high quality speech coding at rates between 4.8 and 16 kbit/s
P. Kroon,E.F. Deprettere +1 more
TL;DR: The general structure of this class of coders is reviewed, and the particulars of its members are discussed and the contributions of the various coder parameters to the performance of the coder are examined.
Journal ArticleDOI
G.722: a new CCITT coding standard for digital transmission of wideband audio signals
TL;DR: A tutorial discussion is provided of the adaptive differential PCM (pulse-code modulation) coding method recommended by the group, which covers the subjective performance tests performed, mode initialization and mode switching, data-speed multiplexing, and communication between narrowband and wideband terminals.