# Change just the ylims of the Magnitude plot from the bode TF

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monkey_matlab on 19 Jan 2016
Hello,
I am trying to change the ylims of just the magnitude of the bode TF plot but I get the error "Undefined function 'getoptions' for input arguments of type 'tf'. Can you help me change the ylims of just the magnitude response? Thanks. Here is what I have so far:
w=100;
e=0.3;
lgspA = logspace(0,5,1000);
num=[2*w*e (w^2)];
den=[1 2*w*e (w^2)];
test_sys1=1-tf(num,den);
[MAG,PHASE,W] = bode(test_sys1, lgspA);
W1 = W;
MAG1 = 20*log10(squeeze(MAG));
e=0.5;
num=[2*w*e (w^2)];
den=[1 2*w*e (w^2)];
test_sys2=1-tf(num,den);
[MAG,PHASE,W] = bode(test_sys2, lgspA);
W2 = W;
MAG2 = 20*log10(squeeze(MAG));
bode(test_sys1,test_sys2);
ylims = getoptions(test_sys1,'YLim'); % size of ylims for this plot will be 2x1 (mag; phase);
ylims{1} = [-60,10];
setoptions(test_sys1,'YLimMode','manual','YLim',ylims)
legend('e=0.3','e=0.5');

Star Strider on 19 Jan 2016
Use the bodeplot function instead of bode. It will allow you to use the setoptions function.

Martin Hartenberger on 7 Sep 2021
Edited: Martin Hartenberger on 7 Sep 2021
You have to first search for all the axes objects in the figure. The third one is the axis of the magnitude plot. After setting this axis as your current one, you can edit the axis limits with ylim and xlim:
G = tf(1,[1,0]);
f1 = bode(G);
axes_handles = findall(f1, 'type', 'axes');
axes(axes_handles(3))
ylim([-60,5])
Leslie Lamontagne on 5 Apr 2023
This method also works when using the margin function to plot bode. Thanks!