diff --git a/matlab/SetCustomExcite.m b/matlab/SetCustomExcite.m
index 823886d..3f2359d 100644
--- a/matlab/SetCustomExcite.m
+++ b/matlab/SetCustomExcite.m
@@ -1,4 +1,19 @@
-function FDTD = SetCustomExcite(FDTD,f0,funcStr);
+function FDTD = SetCustomExcite(FDTD,f0,funcStr)
+% function FDTD = SetCustomExcite(FDTD,f0,funcStr)
+%
+% f0 : nyquist rate
+% funcStr : string desribing the excitation function e(t)
+%
+% see also SetSinusExcite SetGaussExcite
+%
+% e.g for a ramped sinus excite...
+% T = 1/f0;
+% FDTD = SetCustomExcite(FDTD,1e9,..
+% [ '(1-exp(-1*(t/' num2str(T) ')^2) ) * sin(2*pi*' num2str(f0) '*t)' ]);
+%
+% openEMS matlab interface
+% -----------------------
+% author: Thorsten Liebig
 
 FDTD.Excitation.ATTRIBUTE.Type=10;
 FDTD.Excitation.ATTRIBUTE.f0=f0;
diff --git a/matlab/SetGaussExcite.m b/matlab/SetGaussExcite.m
index a5f624e..6e34e79 100644
--- a/matlab/SetGaussExcite.m
+++ b/matlab/SetGaussExcite.m
@@ -1,4 +1,16 @@
-function FDTD = SetGaussExcite(FDTD,f0,fc);
+function FDTD = SetGaussExcite(FDTD,f0,fc)
+% function FDTD = SetSinusExcite(FDTD,f0,fc);
+%
+% f0 : center frequency
+% fc : 3dB cutoff frequency --> bandwidth is 2*fc
+%
+% see also SetSinusExcite SetCustomExcite
+%
+% e.g FDTD = SetGaussExcite(FDTD,1e9,1e8);
+%
+% openEMS matlab interface
+% -----------------------
+% author: Thorsten Liebig
 
 FDTD.Excitation.ATTRIBUTE.Type=0;
 FDTD.Excitation.ATTRIBUTE.f0=f0;
diff --git a/matlab/SetSinusExcite.m b/matlab/SetSinusExcite.m
index 08c1b18..3c5c55d 100644
--- a/matlab/SetSinusExcite.m
+++ b/matlab/SetSinusExcite.m
@@ -1,4 +1,13 @@
-function FDTD = SetGaussExcite(FDTD,f0);
+function FDTD = SetSinusExcite(FDTD,f0)
+% function FDTD = SetSinusExcite(FDTD,f0)
+%
+% see also SetGaussExcite SetCustomExcite
+%
+% e.g FDTD = SetSinusExcite(FDTD,1e9);
+%
+% openEMS matlab interface
+% -----------------------
+% author: Thorsten Liebig
 
 FDTD.Excitation.ATTRIBUTE.Type=1;
 FDTD.Excitation.ATTRIBUTE.f0=f0;
\ No newline at end of file