Title :
Direct coding of a class of non-stationary signals based on mixed transforms
Author :
Mikhael, Wasfy B. ; Spanias, Andreas S.
Author_Institution :
Dept. of Electr. & Comput. Eng., West Virginia Univ., Morgantown, WV, USA
Abstract :
A mixed Fourier-Walsh signal representation is proposed for transform coding. Basis functions from two transforms are used, namely, the discrete Fourier transform (DFT) and the Walsh-Hadamard transform (WHT). An iterative algorithm is used to implement the mixed representation. A finite number of DFT components is used to represent the selective (narrowband) dominant spectrum of speech on a frame-by-frame basis. The whitened (broadband) residual signal is represented using a small number of Walsh components. The parameters of the mixed representation are coded directly by coding the DFT and WHT components. Results are given for frame-by-frame and packet coding at rates ranging from 16 kb/s to 9.6 kb/s
Keywords :
Fourier transforms; Walsh functions; encoding; iterative methods; signal processing; 9.6 to 16 kbit/s; DFT; WHT; Walsh-Hadamard transform; direct coding; discrete Fourier transform; frame-by-frame coding; iterative algorithm; mixed Fourier-Walsh signal representation; mixed transforms; nonstationary signals; packet coding; speech spectrum; transform coding; Discrete Fourier transforms; Discrete transforms; Fourier transforms; Iterative algorithms; Narrowband; Signal representations; Signal synthesis; Speech; Time domain analysis; Transform coding;
Conference_Titel :
Circuits and Systems, 1989., IEEE International Symposium on
Conference_Location :
Portland, OR
DOI :
10.1109/ISCAS.1989.100345
