This is a symbol integrator. It likes a discrete integator that resets to zero afer the summation of nech samples.
[y[,z]] = intsym(u,nech[,initc,step,z])
//one vector of 100 symbols y = genint(100,1,1,2); //16-QAM modulation [yi,yq] = modqam(y,16); //up-sample by 8 yi_s = upsmpl(yi,8,1); //compute Root Raised Cosine impulse //roll-off=0.35, length 128 pulse = filter_tap(1,128,8,0.35,1); //filtering vector of I/Q components i = nfilter(yi_s,pulse'); //symbol i integration g_i = intsym(i,8,5);