Offset Tracking in RPE/LTP Coder
Original Publication Date: 1989-Jun-01
Included in the Prior Art Database: 2005-Jan-28
At the analysis side of a RPE/LTP speech coder, the speech signal s(n) is analyzed by short term prediction, and filtered by the optimal inverse filter A(z). The residual signal r(n) is then analyzed by long- term prediction (LTP), and the error signal x(n) is modelized by regular pulse excited (RPE) coding. The LTP loop allows producing the estimated residual signal x''(n) to be subtracted from the input residual signal r(n) to give the error signal x(n). (Image Omitted) Referring to the figures, transmitted information consists in a set of parcor coefficients K(i) describing the vocal tract, a set of LTP coefficients (b,M), and the grid numbers j associated with the quantized sub-sampled sequences xj'(n).