Title :
On reducing computational complexity of codebook search in CELP coder through the use of algebraic codes
Author :
Laflamme, C. ; Adoul, J.-P. ; Su, H.Y. ; Morissette, S.
Author_Institution :
Sherbrooke Univ., Que., Canada
Abstract :
A general framework is introduced which allows both fast search and freedom in designing codebooks with good statistical properties. Several previously proposed schemes are compared from this viewpoint. A backward filtering formulation is given to show that sparse algebraic codes (SACs) (i.e., with few nonzero components) offer distinct advantages. It is shown that they reduce the optimal-search computation per codeword. They also allow control of the statistical properties of the codebook in the time and frequency domains. This control can be dynamic in the sense that it can be made to evolve as a function of the linear predictive coding model A(z). The algebraic-code excited linear prediction (ACELP) technology which allows full duplex operation on a single TMS320C25 at rates between 4.8 and 16 kb/s and which is based on SAC-driven dynamic codebooks is described
Keywords :
computational complexity; decoding; encoding; filtering and prediction theory; speech analysis and processing; vocoders; 4.8 to 16 kbit/s; ACELP; CELP coder; SAC-driven dynamic codebooks; TMS320C25; algebraic-code excited linear prediction; backward filtering; codebook search; computational complexity; full duplex operation; linear predictive coding model; sparse algebraic codes; statistical properties; Computational complexity; Error correction; Error correction codes; Filtering; Frequency domain analysis; Lattices; Linear predictive coding; Predictive models; Sparse matrices; Speech; Stochastic processes; Technological innovation;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 1990. ICASSP-90., 1990 International Conference on
Conference_Location :
Albuquerque, NM
DOI :
10.1109/ICASSP.1990.115567
