Signal put through an RC filter. Stemmed plot is not matching the shape of the signal, how do I correct this?

I have put a 16-QAM modulated signal through a raised cosine filter. I get a plot of the signal with stems on the same graph. However the stemmed plot is not matching with the shape of the signal. How do I sort this out. I have to change something with the RC filter to get the stemmed plot matching the signal shape, but what do I change?

% RC (Raised Cosine) Filter
  num = rcosine(1,8);            %designs(FIR) RC filter,returns transfer func
  q = rcosflt([1;0;0],1,8,'filter',num);