Analysis-by-synthesis speech coding method with truncation of the impulse response of a perceptual weighting filter
First Claim
1. An analysis-by-synthesis speech coding method for coding a speech signal digitized into successive frames which are subdivided into sub-frames, each sub-frame having a predetermined number of samples, the method comprising the steps of:
- performing a linear prediction analysis of the speech signal for each frame in order to determine coefficients of a short-term synthesis filter;
performing an open-loop analysis for each frame in order to determine a degree of voicing of the frame; and
performing at least one closed-loop analysis for each sub-frame in order to determine an excitation sequence which, submitted to the short-term synthesis filter, produces a synthetic signal representative of the speech signal, each closed-loop analysis using an impulse response of a composite filter consisting of the short-term synthesis filter and of a perceptual weighting filter, said impulse response being truncated to a truncation length which does not exceed said predetermined number of samples per sub-frame and which depends on an energy distribution of said response and on the degree of voicing of the frame.
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Abstract
A linear prediction analysis is performed for each frame of a speech signal to determine the coefficients of a short-term synthesis filter and an open-loop analysis is performed to determine a degree of frame voicing. At least one closed-loop analysis is performed for each sub-frame to determine an excitation sequence which, when applied to the short-term synthesis filter, generates a synthetic signal representative of the speech signal. Each closed-loop analysis uses the impulse response of a filter consisting of the short-term synthesis filter and a perceptual weighting filter, by truncating the impulse response to a truncation length that is no greater than the number of samples per sub-frame and is dependent on the energy distribution of the response and the degree of voicing of the frame.
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Citations
5 Claims
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1. An analysis-by-synthesis speech coding method for coding a speech signal digitized into successive frames which are subdivided into sub-frames, each sub-frame having a predetermined number of samples, the method comprising the steps of:
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performing a linear prediction analysis of the speech signal for each frame in order to determine coefficients of a short-term synthesis filter; performing an open-loop analysis for each frame in order to determine a degree of voicing of the frame; and performing at least one closed-loop analysis for each sub-frame in order to determine an excitation sequence which, submitted to the short-term synthesis filter, produces a synthetic signal representative of the speech signal, each closed-loop analysis using an impulse response of a composite filter consisting of the short-term synthesis filter and of a perceptual weighting filter, said impulse response being truncated to a truncation length which does not exceed said predetermined number of samples per sub-frame and which depends on an energy distribution of said response and on the degree of voicing of the frame. - View Dependent Claims (2, 3, 4, 5)
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Specification