Title :
Mixed Fourier/Walsh transform scheme for speech coding at 4.0 kbit/s
Author :
Spanias, A.S. ; Loizou, P.C.
Author_Institution :
Dept. of Electr. Eng., Arizona State Univ., Tempe, AZ, USA
Abstract :
A mixed Fourier/Walsh transform scheme for speech coding is proposed. A set of harmonically structured frequency components is used to represent narrowband components of speech. The broadband residual is characterised by a small number of sequency components. The frequencies and sequences of the transform components are determined by sampling the short-time Fourier and Walsh transforms, respectively. The magnitudes and phases of the Fourier components and the amplitudes of the Walsh components are determined using an iterative algorithm based on the Gauss-Seidel method. A vector quantisation (VQ) scheme is developed to encode the frequency and the sequency components. Results and subjective evaluations are given for speech coding at 4.0 kbit/s.<>
Keywords :
data compression; encoding; fast Fourier transforms; iterative methods; speech analysis and processing; 4.0 kbit/s; DFT; Fourier components; Fourier/Walsh transform; Gauss-Seidel; VQ; Walsh components; broadband residual; harmonically structured frequency components; iterative algorithm; magnitudes; narrowband components; phases; sequency components; short time Fourier transform; speech coding; subjective evaluations; transform components; vector quantisation;
Journal_Title :
Communications, Speech and Vision, IEE Proceedings I
