function [es, DecoderMem] = GenExcSID (QC, DecoderMem, DecoderPar)% SID frame decoder% DecoderMem.CNG.SIDGain is updated to the received gain value% DecoderMem.CNG.Gain is updated to the smoothed gain value% $Id: GenExcSID.m 1.3 2004/07/09 G.723.1-v2r1b $CNGpar = DecoderPar.CNGpar;% Extract the codesGainC = QC.GainC;% Gain calculationSIDGain = CNGpar.GainCBook(GainC + 1);   % Decode the transmitted gainGainP = DecoderMem.CNG.Gain;             % Previous gain% Update the gain valueFModeP = DecoderMem.CNG.FModeP;if (FModeP == 0 | FModeP == 1 | FModeP == 2)  % Previous: normal transmitted frame  GainT = SIDGain;else                                          % Previous: SID or null  a = CNGpar.GFactor;  GainT = (1 - a) * GainP + a * SIDGain;endDecoderMem.CNG.SIDGain = SIDGain;DecoderMem.CNG.Gain = GainT;% Generate a CNG frame[es, DecoderMem] = GenExcCNG (GainT, DecoderMem, DecoderPar);return