Speech coding/decoding using phase spectrum corresponding to...

Details Speech coding/decoding using phase spectrum corresponding to... Speech coding/decoding using phase spectrum corresponding to...

1998-03-10

2001-04-17

Dorvil, Richemond (Department: 2741)

Data processing: speech signal processing, linguistics, language

Speech signal processing

For storage or transmission

C704S230000, C704S264000

Reexamination Certificate

active

06219637

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is concerned with speech coding and decoding, and especially with systems in which the coding process fails to convey all or any of the phase information contained in the signal being coded.
2. Related Art
A known speech coder and decoder is shown in FIG.
1
and is further discussed below. However, such prior art is based on assumptions regarding the phase spectrum which can be further improved.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided a decoder for speech signals comprising:
means for receiving magnitude spectral information for synthesis of a time-varying signal;
means for computing, from the magnitude spectral information, phase spectrum information corresponding to a minimum phase filter which has a magnitude spectrum corresponding to the magnitude spectral information;
means for generating, from the magnitude spectral information and the phase spectral information, the time-varying signal; and
phase adjustment means operable to modify the phase spectrum of the signal.
In another aspect the invention provides a decoder for decoding speech signals comprising information defining the response of a minimum phase synthesis filter and, for synthesis of an excitation signal, magnitude spectral information, the decoder comprising:
means for generating, from the magnitude spectral information, an excitation signal;
a synthesis filter controlled by the response information and connected to filter the excitation signal; and
phase adjustment means for estimating a phase-adjustment signal to modify the phase of the signal.
In a further aspect, the invention provides a method of coding and decoding speech signals, comprising:
(a) generating signals representing the magnitude spectrum of the speech signal;
(b) receiving the signals;
(c) generating from the received signals a synthetic speech signal having a magnitude spectrum determined by the received signals and having a phase spectrum which corresponds to a transfer function having, when considered as a z-plane plot, at least one pole outside the unit circle.


REFERENCES:
patent: 4475227 (1984-10-01), Belfield
patent: 4626828 (1986-12-01), Nishitani
patent: 4782523 (1988-11-01), Galand et al.
patent: 4969192 (1990-11-01), Chen et al.
patent: 5862227 (1999-01-01), Orduna-Bustamante et al.
patent: 0259950 A1 (1988-03-01), None
patent: 0698876 A2 (1996-02-01), None
Ozawa, A 4.8 kb/s High-Quality Speech Coding Using Various Types of Excitation Signals, Proceedings of the European Conference on Speech Communication and Technology (Eurospeech), Paris, Sep. 26-28, 1989, vol. 1, Sep. 26, 1989, pp. 306-309.
McAulay et al, “19 Sine-Wave Amplitude Coding at Low Data Rates”, Advances in Speech Coding, Vancouver, Sep. 5-8, 1989, Jan. 1, 1991, pp. 203-213.
Arjmand et al, “Pitch-Congruent Baseband Speech Coding”, Proceedings of ICASSP 83, IEEE International Conference on Acoustics, Speech and Signal Processing, Boston, MA, Apr. 14-16, 1983, 1983 New York, NY IEEE USA, pp. 1324-1327, vol.3.
Kleijn, “Continuous Representations in Linear Predictive Coding”, IEEE, 1991.
Kleijn et al, “A General Waveform-Interpolation Structure for Speech Coding”, Signal Processing, pp. 1665-1668, 1994.
Kleijn et al, “A Speech Coder Based on Decomposition of Characteristic Waveforms”, 1995, IEEE, pp. 508-511.
McAulay et al, “Speech Analysis/Synthesis Based on a Sinusoidal Representation”, IEEE Transactions on Acoustics, Speech, and Signal Processing, vol. ASSP-34, No. 4, Aug. 1986, pp. 744-754.
Rosenberg, “Effect of Glottal Pulse Shape on the Quality of Natural Vowels”, The Journal of the Acoustical Society of America, pp. 583-590, Apr. 1970.

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