This definitely isn't a homework question as the work is already done, I'm just trying to make my presentation neater for some reports I'm turning in. I am comparing theoretical data collected from a filter, to the actual data collected. I want to overlay the two to make the comparison. I am trying to do this for both the gain, and the phase difference. I have a plot for the gain, I have a plot for the phase difference, and I have the bodeplot that has both. But I can't seem to overlay everything. Here is the code I have if any matlab whizzes can help me figure out how to do it. All of the plots themselves are correct, I don't need help with them. I just want to overlay the gain plot and phase plot over the respective parts of the bode plot. sys=tf([0 -8200], [0 .12874 1570]) bodeplot(sys) %this is the bodeplot for the theoretical values x=[100 1885 3142 10681 12566 14451 31416 628318 1000000]; %start of the gain plot for data V=[10.2 10.2 9.8 7.6 7 6.4 3.8 .3 0]; y=20*log10(V./2); subplot(2,1,1); semilogx(x,y,'r') %this is the end of gain plot for data P=[189 189 165 140 136 126 116 92 92]; subplot(2,1,2); semilogx(x,P,'r') %This is the phase plot for real data % subplot plots both the gain and phase plots together simply adding a "hold on" command in there doesn't over lay the bode plot on the other plots. Any suggestions or commands anybody can think of the get everything lined up?