Coding of acoustic waveforms
First Claim
Patent Images
1. A method of coding speech for digital transmission, the method comprising:
- sampling the speech to obtain a series of discrete samples and constructing therefrom a series of frames, each frame spanning a plurality of samples;
analyzing each frame of samples to extract a set of variable frequency components having individual amplitudes and phases which, in summation, approximate the waveform of the speech frame;
estimating a pitch for each frame of samples;
coding data representative of the analyzed speech frame and the pitch for digital transmission;
synthesizing a set of reconstruction frequency components from the encoded data; and
establishing a pitch onset time at which the frequency components come into phase synchrony.
0 Assignments
0 Petitions
Accused Products
Abstract
Encoding techniques and devices are based on a sinusoidal speech representation model. In one aspect of the invention, a pitch-adaptive channel encoding technique for amplitude coding varies the channel spacing in accordance with the pitch of the speaker'"'"'s voice. In another aspect of the invention, a phase synthesis technique locks rapidly-varying phases into synchrony with the phase of the fundamental. Phase coding techniques which introduce a voice-dependent random phase and a pitch-adaptive quadratic phase dispersion are also performed.
-
Citations
23 Claims
-
1. A method of coding speech for digital transmission, the method comprising:
-
sampling the speech to obtain a series of discrete samples and constructing therefrom a series of frames, each frame spanning a plurality of samples; analyzing each frame of samples to extract a set of variable frequency components having individual amplitudes and phases which, in summation, approximate the waveform of the speech frame; estimating a pitch for each frame of samples; coding data representative of the analyzed speech frame and the pitch for digital transmission; synthesizing a set of reconstruction frequency components from the encoded data; and establishing a pitch onset time at which the frequency components come into phase synchrony. - View Dependent Claims (2, 3, 4, 5, 6)
-
-
7. A method of coding speech for digital transmission, the method comprising:
-
sampling the speech to obtain a series of discrete samples and constructing therefrom a series of frames, each frame spanning a plurality of samples; analyzing each frame of samples to extract a set of variable frequency components having individual amplitudes and phases; estimating the pitch for each frame of samples; constructing a spectral envelope from the amplitudes of the frequency components; sampling the envelope based upon the pitch estimate to obtain a set of amplitude values at variable channel frequencies, the location of which vary with the pitch; coding the amplitude values for digital transmission; and synthesizing a set of reconstruction frequency components from the encoded values. - View Dependent Claims (8, 9)
-
-
10. A speech coding device comprising:
-
sampling means for sampling a speech waveform to obtain a series of discrete samples and constructing therefrom a series of frames, each frame spanning a plurality of samples; analyzing means for analyzing each frame of samples by Fourier analysis to extract a set of variable frequency components having individual amplitude and phase values; estimating means for estimating the pitch for each frame of samples; coding means for coding data representative of the analyzed speech frame and a pitch for each frame; synthesizing means for synthesizing a set of reconstruction frequency components from the encoded data; and means for establishing a pitch onset time at which the frequency components come into phase synchrony. - View Dependent Claims (11, 12, 13, 14, 15)
-
-
16. A speech coding device comprising:
-
sampling means for sampling a speech waveform to obtain a series of discrete samples and constructing therefrom a series of frames, each frame spanning a plurality of samples; analyzing means for analyzing each frame of samples by Fourier analysis to extract a set of variable frequency components having individual amplitude and phase values; estimating means for estimating the pitch of the waveform; envelope construction means for constructing a spectral envelope from the amplitudes of the frequency components; envelope sampling means for sampling the envelope based upon the pitch estimate to obtain a set of amplitude values at variable channel frequencies, the number and spacing of which vary based upon the pitch; coding means for coding the amplitude values for digital transmission; and synthesizing means for synthesizing a set of reconstruction frequency components from the encoded values. - View Dependent Claims (17, 18)
-
-
19. A system for processing an acoustic waveform comprising:
-
analyzing means for decomposing the waveform into a set of sinusoidal components having individual amplitudes which in sum approximate the waveform over an analysis frame; pitch estimating means for estimating the pitch of the waveform for the analysis frame; and synthesis means for generating a synthetic reproduction of the waveform from the data representative of the analyzed waveform and the pitch, including means for summing a set of sinusoidal reconstruction components and means for establishing a pitch onset time for each analysis frame at which time the phases of the sinusoidal reconstruction components come into synchrony. - View Dependent Claims (20, 21, 22, 23)
-
Specification