Remove 50Hz and harmonics from ground motion

org/disturbances.org

@@ -243,7 +243,6 @@ The transfer functions from the disturbance forces to the relative velocity of t
 
   io(io_i) = linio([mdl, '/Micro-Station/Granite/Modal Analysis/accelerometer'], 1, 'openoutput'); io_i = io_i + 1; % Absolute motion - Granite
   io(io_i) = linio([mdl, '/Micro-Station/Micro Hexapod/Modal Analysis/accelerometer'],  1, 'openoutput'); io_i = io_i + 1; % Absolute Motion - Hexapod
-  % io(io_i) = linio([mdl, '/Vm'],   1, 'openoutput'); io_i = io_i + 1; % Relative Velocity hexapod/granite
 
   % Run the linearization
   G = linearize(mdl, io, 0);
@@ -373,6 +372,15 @@ Also, the Ground Motion is measured.
   tyx.pxe_ty_r = tyx.pxe_ty_r(2:end); % PSD of Relative Velocity [(m/s)^2/Hz]
 #+end_src
 
+Because some 50Hz and harmonics were present in the ground motion measurement, we remove these peaks with the following code:
+#+begin_src matlab
+  f0s = [50, 100, 150, 200, 250, 350, 450];
+  for f0 = f0s
+      i = find(gm.f > f0-0.5 & gm.f < f0+0.5);
+      gm.psd_gm(i) = linspace(gm.psd_gm(i(1)), gm.psd_gm(i(end)), length(i));
+  end
+#+end_src
+
 We now compute the relative velocity between the hexapod and the granite due to ground motion.
 #+begin_src matlab
   gm.psd_rv = gm.psd_gm.*abs(squeeze(freqresp(G('Vm', 'Dw'), gm.f, 'Hz'))).^2;