Patent ID: 7593852

Claim:
A method of encoding an input speech signal to generate an encoded speech, the method comprising: selecting one of a first framing structure and a second framing structure for encoding parameters of a frame of the input speech signal; determining a pitch characteristic for each of a plurality of subframes of the frame of the input speech signal, when the second framing structure is selected, wherein the determining the pitch characteristic is performed as a function of prediction coefficients associated with each of the plurality of subframes; searching a 3-pulse codebook including pulses having relative positions with respect to each other, when the second framing structure is selected, to determine a fixed codebook excitation vector with three pulses having the relative positions with respect to each other; enhancing the fixed codebook excitation vector using the pitch characteristic to generate an enhanced fixed codebook excitation vector; determining a fixed codebook gain for each of the plurality of subframes, when the second framing structure is selected, based on the enhanced the fixed codebook excitation vector; and generating the encoded speech using the fixed codebook gain.