You can interpolate one of the signals to make them the same size. Something like this:
Signal1 = (linspace(1,30,30))';
Signal2 = (linspace(1,30,180))';
Signal1_int = interp1(1:size(Signal1,1),Signal1.',linspace(1,size(Signal1,1),size(Signal2,1)))';
Now you can plot both signals in one plot.
Or just use hold on and hold off.