Method and device for encoding wideband speech
First Claim
1. A wideband speech encoding method comprising:
- sampling the speech to obtain successive voice frames each comprising a predetermined number of samples, and each voice frame having determined parameters of a code-excited linear prediction model, the parameters comprising a long-term excitation digital word extracted from an adaptive coded directory, and an associated long-term gain, and a short-term excitation word extracted from a fixed coded directory and an associated short-term gain; and
updating the adaptive coded directory on the basis of the extracted long-term excitation word and of the extracted short-term excitation word, and comprisingadding the product of the long-term excitation digital word times the associated long-term gain with the product of the short-term excitation word times the associated short-term gain to generate a summed digital word, andfiltering the summed digital word with a low-pass filter having a cutoff frequency greater than a quarter and less than a half of a sampling frequency to obtain a filtered word, andupdating the adaptive coded directory with the filtered word.
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Abstract
The speech is sampled in such a way as to obtain successive voice frames each including a predetermined number of samples, and with each voice frame are determined parameters of a code-excited linear prediction model. The parameters include a long-term excitation digital word vi extracted from an adaptive coded directory LTD, and an associated long-term gain Ga, as well as a short-term excitation word cj extracted from a fixed coded directory STD and an associated short-term gain Gc. The product of the long-term excitation extracted word times the associated long-term gain is summed SM with the product of the short-term excitation extracted word times the associated short-term gain. The summed digital word is filtered in a low-pass filter FLCT having a cutoff frequency greater than a quarter of the sampling frequency and less than a half of the latter, and the adaptive coded directory is updated with the filtered word.
11 Citations
36 Claims
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1. A wideband speech encoding method comprising:
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sampling the speech to obtain successive voice frames each comprising a predetermined number of samples, and each voice frame having determined parameters of a code-excited linear prediction model, the parameters comprising a long-term excitation digital word extracted from an adaptive coded directory, and an associated long-term gain, and a short-term excitation word extracted from a fixed coded directory and an associated short-term gain; and updating the adaptive coded directory on the basis of the extracted long-term excitation word and of the extracted short-term excitation word, and comprising adding the product of the long-term excitation digital word times the associated long-term gain with the product of the short-term excitation word times the associated short-term gain to generate a summed digital word, and filtering the summed digital word with a low-pass filter having a cutoff frequency greater than a quarter and less than a half of a sampling frequency to obtain a filtered word, and updating the adaptive coded directory with the filtered word. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A wideband speech encoding method comprising:
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sampling the speech to obtain successive voice frames each comprising a predetermined number of samples, and each voice frame having parameters of a code-excited linear prediction model, the parameters comprising a long-term excitation digital word extracted from an adaptive coded directory, and, an associated long-term gain, and a short-term excitation word extracted from a fixed coded directory and, an associated short-term gain; and updating the adaptive coded directory on the basis of the extracted long-term excitation word and of the extracted short-term excitation word, and comprising adding the product of the long-term excitation digital word times the associated long-term gain with the product of the short-term excitation word times the associated short-term gain to generate a summed digital word, and filtering the summed digital word to obtain a filtered word, and updating the adaptive coded directory with the filtered word. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A wideband speech encoding device comprising:
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sampling means for sampling the speech to obtain successive voice frames each comprising a predetermined number of samples; processing means for determining parameters of a code-excited linear prediction model with each voice frame, and comprising first extraction means for extracting a long-term excitation digital word from an adaptive coded directory and calculating an associated long-term gain, and second extraction means for extracting a short-term excitation word from a fixed coded directory and calculating an associated short-term gain; and first updating means for updating the adaptive coded directory on the basis of the extracted long-term excitation word and of the extracted short-term excitation word, and comprising first calculation means for summing the product of the long-term excitation extracted word times the associated long-term gain, with the product of the short-term excitation extracted word times the associated short-term gain, to deliver a summed digital word, and a low-pass filter having a cutoff frequency greater than a quarter and less than a half of a sampling frequency to generate a filtered word, and connected between an output of the first calculation means and the adaptive coded directory to update the adaptive directory with the filtered word. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26)
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27. A wideband speech encoding device comprising:
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a sampler to sample the speech to obtain successive voice frames each comprising a predetermined number of samples; a processor to determine parameters of a code-excited linear prediction model with each voice frame, and comprising a first extractor to extract a long-term excitation digital word from an adaptive coded directory and calculate an associated long-term gain, and a second extractor to extract a short-term excitation word from a fixed coded directory and calculate an associated short-term gain; and a first updating unit to update the adaptive coded directory on the basis of the extracted long-term excitation word and of the extracted short-term excitation word, and comprising a first calculation unit to add the product of the long-term excitation extracted word times the associated long-term gain, with the product of the short-term excitation extracted word times the associated short-term gain, to deliver a summed digital word, and a low-pass filter to generate a filtered word, and connected between an output of the first calculation unit and the adaptive coded directory to update the adaptive coded directory with the filtered word. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification