            Syn_filt(Az, exc_enhanced, &synth[i_subfr], L_SUBFR, st->mem_syn, 0);         }         else         {            Copy(&synth[i_subfr+L_SUBFR-M], st->mem_syn, M);         }           *--------------------------------------------------*          * Update signal for next frame.                    *          * -> shift to the left by L_SUBFR  st->exc[]       *          *--------------------------------------------------*          