Location and coding of unvoiced plosives in linear predictive coding of speech

摘要

A method of encoding signal segments which represent unvoiced plosives. The signal segments to be encoded are contained within a speech signal divided into m1, . . . , N frames. Each frame is subdivided into l1, . . . , L subframes. The speech signal has a gain g^m(l) within each subframe. An energy measure e^m(l) representative of the signal segments' energy content is defined. An energy threshold e_th(l) representative of a sudden energy change characteristic of an unvoiced plosive is also defined. For each frame, the energy measure e^m(l) and the energy threshold e_th(l) are derived for each subframe within that frame. If e^m(l)e_th(l) for each subframe within a particular frame, then a plosive locator l_pl0 and a plosive index i_pl0 are assigned to that frame to indicate absence of a plosive within that frame. If e^m(l)e_th(l) for any subframe within the frame, then that frame's plosive locator l_pl is assigned a non-zero value, with the plosive locator's value indicating location of the plosive at a transition point immediately following that one of the subframes within the frame for which e^m(l)e_th(l) is greatest; and, that frame's plosive index i_pl is assigned a non-zero value representing presence of a plosive within that frame.