Title :
Lattice low-delay vector excitation coding of speech at 8-16 kb/s
Author :
Cuperman, V. ; Rong Peng
Author_Institution :
Sch. of Eng. Sci., Simon Fraser Univ., Burnaby, BC
fDate :
6/1/1994 12:00:00 AM
Abstract :
Lattice low-delay vector excitation coding (LLD-VXC) is a speech coding system based on analysis-by-synthesis excitation coding and backward adaptation of the synthesis filter. The introduction of a lattice filter as a (high order) short-term predictor has significant advantages, such as fast tracking of speech signal nonstationarities, simple stability verification, and uniform distribution of the computational load. The objective of this paper is to present a Lattice LD-VXC (LLD-VXC) codec-and experimental results obtained at rates of 8, 9.6, and 16 kb/s. A sign algorithm for lattice filter adaptation is introduced in order to reduce computational complexity. An LLD-VXC codec with a 20th-order lattice predictor, a 10th-order lattice weighting filter, and a backward pitch predictor achieved toll quality at 16 kb/s and good communications quality at 8-9.6 kb/s with a delay of less than 2 ms and reasonable complexity
Keywords :
adaptive filters; codecs; digital filters; linear predictive coding; speech analysis and processing; speech coding; speech synthesis; 8 to 16 kbit/s; analysis-by-synthesis; backward adaptation; backward pitch predictor; codec; communications quality; computational complexity; computational load; fast tracking; lattice filter adaptation; lattice low-delay; lattice predictor; lattice weighting filter; short-term predictor; sign algorithm; speech coding; speech signal nonstationarities; stability verification; synthesis filter; toll quality; uniform distribution; vector excitation coding; Codecs; Computational complexity; Distributed computing; Filters; Lattices; Signal synthesis; Speech analysis; Speech coding; Speech synthesis; Stability;
Journal_Title :
Communications, IEEE Transactions on
