Speech coding system and method
First Claim
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1. A speech coding system comprising:
- memory means for storing successive frames of a digitized speech signal;
means connected to said memory means for producing a parameter signal representative of a spectral envelope of said speech signal by analyzing said digitized speech signal for each of said successive frames;
means including an inverse filter connected to receive said digitized speech signal and said parameter signal for producing a residual pulse train for each frame of said digitized speech signal;
excitation extracting means coupled to said inverse filter for dividing said residual pulse train for each frame into a plurality of sub-frames and for extracting a pulse having a peak amplitude from said residual pulse train within each sub-frame, and including means for producing an information signal indicative of the amplitude and location of said peak amplitude pulse as excitation information; and
coding means coupled to said parameter signal producing means and said excitation extracting means for coding said parameter signal and said information signal to produce a coded speech signal.
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Abstract
In a speech coding method and system in which a speech signal is analyzed in each frame so as to be separated into spectral envelope information and excitation information and both of the information are coded, each frame is divided into a plurality of sub-frames and a pulse of the maximum-amplitude is extracted from pulses within each sub-frame in order to provide large-amplitude pulses from each frame, thereby greatly reducing the number of pulse extracting processing steps.
18 Citations
12 Claims
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1. A speech coding system comprising:
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memory means for storing successive frames of a digitized speech signal; means connected to said memory means for producing a parameter signal representative of a spectral envelope of said speech signal by analyzing said digitized speech signal for each of said successive frames; means including an inverse filter connected to receive said digitized speech signal and said parameter signal for producing a residual pulse train for each frame of said digitized speech signal; excitation extracting means coupled to said inverse filter for dividing said residual pulse train for each frame into a plurality of sub-frames and for extracting a pulse having a peak amplitude from said residual pulse train within each sub-frame, and including means for producing an information signal indicative of the amplitude and location of said peak amplitude pulse as excitation information; and coding means coupled to said parameter signal producing means and said excitation extracting means for coding said parameter signal and said information signal to produce a coded speech signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A speech coding system comprising:
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memory means for storing successive frames of a digitized speech signal; means connected to said memory means for producing a parameter signal representative of a spectral envelope of said speech signal by analyzing said digitized speech signal for each of said successive frames; means including an inverse filter connected to receive said digitized speech signal and said parameter signal for producing a residual pulse train for each frame of said digitized speech signal; excitation extracting means coupled to said inverse filter for dividing said residual pulse train for each frame into a plurality of sub-frames and for extracting a pulse having a peak amplitude from said residual pulse train within each sub-frame, and including means for producing an information signal indicative of the amplitude and location of said peak amplitude pulse as excitation information; coding means coupled to said parameter signal producing means and said excitation extracting means for coding said parameter signal and said information signal to produce a coded speech signal; decoding means connected to receive said coded speech signal for producing a parameter signal representative of a spectral envelope of said speech signal and an information signal identifying a residual pulse location and amplitude of a pulse for each successive sub-frame of a frame; regenerator means coupled to said decoding means for generating an excitation pulse train based on said residual pulse location and amplitude information indicated by said information signal; and means, coupled to said coding means and said regenerator means and including a synthesis filter, for producing a synthesized speech signal in response to said parameter signal and said excitation pulse train. - View Dependent Claims (11)
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12. A speech coding method comprising the steps of:
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analyzing successive frames of a digitized speech signal in each frame so as to produce a parameter signal representing a spectral envelope of said speech signal; producing a residual pulse train in accordance with said parameter signal and said speech signal for each frame of said speech signal; dividing each frame of said residual pulse train into a plurality of sub-frames; detecting a pulse having peak amplitude from the residual pulse train within each sub-frame and its location; and coding a location and amplitude of said detected peak amplitude residual pulse for each sub-frame into excitation information.
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Specification