Determining linear predictive coding filter parameters for...

Details Determining linear predictive coding filter parameters for... Determining linear predictive coding filter parameters for...

2003-05-28

2004-08-24

McFadden, Susan (Department: 2655)

Data processing: speech signal processing, linguistics, language

Speech signal processing

For storage or transmission

C704S220000, C704S222000

Reexamination Certificate

active

06782359

ABSTRACT:

BACKGROUND
This invention relates to digital voice coders performing at relatively low voice rates but maintaining high voice quality. In particular, it relates to improved multipulse linear predictive voice coders.
The multipulse coder incorporates the linear predictive all-pole filter (LPC filter). The basic function of a multipulse coder is finding a suitable excitation pattern for the LPC all-pole filter which produces an output that closely matches the original speech waveform. The excitation signal is a series of weighted impulses. The weight values and impulse locations are found in a systematic manner. The selection of a weight and location of an excitation impulse is obtained by minimizing an error criterion between the all-pole filter output and the original speech signal. Some multipulse coders incorporate a perceptual weighting filter in the error criterion function. This filter serves to frequency weight the error which in essence allows more error in the format regions of the speech signal and less in low energy portions of the spectrum. Incorporation of pitch filters improve the performance, of multipulse speech coders. This is done by modeling the long term redundancy of the speech signal thereby allowing the excitation signal to account for the pitch related properties of the signal.
SUMMARY
Linear predictive coding (LPC) filter parameters are determined for use in encoding a voice signal. Samples of a speech signal using a z-transform function are pre-emphasized. The pre-emphasized samples are analyzed to produce LPC reflection coefficients. The LPC reflection coefficients are quantized by a voiced quantizer and by an unvoiced quantizer producing sets of quantized reflection coefficients. Each set is converted into respective spectral coefficients. The set which produces a smaller lag-spectral distance is determined. The determined set is selected to encode the voice signal.


REFERENCES:
patent: 4618982 (1986-10-01), Horvath et al.
patent: 4669120 (1987-05-01), Ono
patent: 4776015 (1988-10-01), Takeda et al.
patent: 4815134 (1989-03-01), Picone et al.
patent: 4845753 (1989-07-01), Yasunaga
patent: 4868867 (1989-09-01), Davidson et al.
patent: 4890327 (1989-12-01), Bertrand et al.
patent: 4980916 (1990-12-01), Zinser
patent: 4991213 (1991-02-01), Wilson
patent: 5001759 (1991-03-01), Fukui
patent: 5027405 (1991-06-01), Ozawa
patent: 5235670 (1993-08-01), Lin et al.
patent: 5265167 (1993-11-01), Akamine et al.
patent: 5307441 (1994-04-01), Tzeng
patent: 5999899 (1999-12-01), Robinson
patent: 6006174 (1999-12-01), Lin et al.
patent: 6223152 (2001-04-01), Lin et al.
patent: 6385577 (2002-05-01), Lin et al.
patent: 6591234 (2003-07-01), Chandran et al.
patent: 6611799 (2003-08-01), Lin et al.
patent: 6633839 (2003-10-01), Kushner et al.
patent: WO8602726 (1986-06-01), None
Proc. ICASSP '82, A New Model of LPC Excitation for Producing Natural-Sounding Speech at Low Bit Rates, B.S. Atal and J.R. Remde, pp 614-617, Apr. 1982.
Proc. ICASSP '84, Improving Performance of Multi-Pulse Coders at Low Bit Rates, S. Singhal and B.S. Atal, paper 1.3, Mar. 1984.
Proc. ICASSP '84, Efficient Computation and Encoding of the Multiple Excitation for LPC, M. Berouti et al., paper 10. Mar. 1, 1984.
Proc. ICASSP '86, Implementation of Multi-Pulse Coder on a Single Chip Floating-Point Signal Processor, H. Alrutz, paper 44. Apr. 3, 1986.
Digital Telephony, John Bellamy, pp 153-154, 1991.
Veeneman et al., Computationally Efficient Stochastic Coding of Speech, 1990, IEEE 40thVehicular Technology Conference, May 1990, pp. 331-335.

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