diff --git a/matlab/FFT_time2freq.m b/matlab/FFT_time2freq.m
new file mode 100644
index 0000000..cdfad45
--- /dev/null
+++ b/matlab/FFT_time2freq.m
@@ -0,0 +1,9 @@
+function [f,val] = FFT_time2freq( t, val )
+
+dt=t(2)-t(1);
+val = [val zeros(1,5000)];
+L=numel(val);
+f = (0:L-1)/L/dt;
+f = f(1:floor(L/2));
+val = 2*fft(val)/L;
+val = val(1:floor(L/2));
diff --git a/matlab/ReadUI.m b/matlab/ReadUI.m
index 0d79a9e..bae9017 100644
--- a/matlab/ReadUI.m
+++ b/matlab/ReadUI.m
@@ -18,11 +18,5 @@ for n=1:numel(filenames)
     UI.TD{n}.t = t;
     UI.TD{n}.val = val;
     
-    dt=t(2)-t(1);
-    val = [val zeros(1,5000)];
-    L=numel(val);
-    UI.FD{n}.f = (0:L-1)/L/dt;
-    UI.FD{n}.f = UI.FD{n}.f(1:floor(L/2));
-    UI.FD{n}.val = 2*fft(val)/L;
-    UI.FD{n}.val = UI.FD{n}.val(1:floor(L/2));
+    [UI.FD{n}.f,UI.FD{n}.val] = FFT_time2freq( t,val );
 end