diff --git a/src/index.org b/src/index.org
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+#+TITLE: Matlab Function useful for the analysis
+
+* voltageToVelocityL22
+  :PROPERTIES:
+  :header-args:matlab+: :tangle voltageToVelocityL22.m
+  :header-args:matlab+: :comments none :mkdirp yes
+  :header-args:matlab+: :eval no :results none
+  :END:
+  <<sec:voltageToVelocityL22>>
+
+This Matlab function is accessible [[file:voltageToVelocityL22.m][here]].
+
+#+begin_src matlab
+  function [velocity] = voltageToVelocityL22(voltage, time, gain)
+  % voltageToVelocityL22 -
+  %
+  % Syntax: [velocity] = voltageToVelocityL22(voltage, time, gain)
+  %
+  % Inputs:
+  %    - voltage - Measured voltage
+  %    - time - Time vector
+  %    - gain - Gain of the voltage amplifier in dB
+  %
+  % Outputs:
+  %    - velocity -
+#+end_src
+
+#+begin_src matlab
+  s = zpk('s');
+#+end_src
+
+#+begin_src matlab
+  S0 = 88; % Sensitivity [V/(m/s)]
+  f0 = 2; % Cut-off frequnecy [Hz]
+
+  S = S0*(s/2/pi/f0)/(1+s/2/pi/f0);
+#+end_src
+
+#+begin_src matlab
+  velocity = lsim((S*10^(gain/20))\1, voltage, time);
+#+end_src
+
+* voltageToDisplacementL22
+  :PROPERTIES:
+  :header-args:matlab+: :tangle voltageToDisplacementL22.m
+  :header-args:matlab+: :comments none :mkdirp yes
+  :header-args:matlab+: :eval no :results none
+  :END:
+  <<sec:voltageToDisplacementL22>>
+
+This Matlab function is accessible [[file:voltageToDisplacementL22.m][here]].
+
+#+begin_src matlab
+  function [disp] = voltageToDisplacementL22(voltage, time, gain)
+  % voltageToDisplacementL22 -
+  %
+  % Syntax: [disp] = voltageToDisplacementL22(voltage, time, gain)
+  %
+  % Inputs:
+  %    - voltage - Measured voltage
+  %    - time - Time vector
+  %    - gain - Gain of the voltage amplifier in dB
+  %
+  % Outputs:
+  %    - disp -
+#+end_src
+
+#+begin_src matlab
+  s = zpk('s');
+#+end_src
+
+#+begin_src matlab
+  voltage = voltage - mean(voltage);
+
+  velocity = voltageToVelocityL22(voltage, time, gain);
+
+  disp = lsim(1/s, velocity, time);
+#+end_src
diff --git a/src/voltageToDisplacementL22.m b/src/voltageToDisplacementL22.m
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+function [disp] = voltageToDisplacementL22(voltage, time, gain)
+% voltageToDisplacementL22 -
+%
+% Syntax: [disp] = voltageToDisplacementL22(voltage, time, gain)
+%
+% Inputs:
+%    - voltage - Measured voltage
+%    - time - Time vector
+%    - gain - Gain of the voltage amplifier in dB
+%
+% Outputs:
+%    - disp -
+
+s = zpk('s');
+
+voltage = voltage - mean(voltage);
+
+velocity = voltageToVelocityL22(voltage, time, gain);
+
+disp = lsim(1/s, velocity, time);
diff --git a/src/voltageToVelocityL22.m b/src/voltageToVelocityL22.m
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index 0000000..4e89cb1
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+++ b/src/voltageToVelocityL22.m
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+function [velocity] = voltageToVelocityL22(voltage, time, gain)
+% voltageToVelocityL22 -
+%
+% Syntax: [velocity] = voltageToVelocityL22(voltage, time, gain)
+%
+% Inputs:
+%    - voltage - Measured voltage
+%    - time - Time vector
+%    - gain - Gain of the voltage amplifier in dB
+%
+% Outputs:
+%    - velocity -
+
+s = zpk('s');
+
+S0 = 88; % Sensitivity [V/(m/s)]
+f0 = 2; % Cut-off frequnecy [Hz]
+
+S = S0*(s/2/pi/f0)/(1+s/2/pi/f0);
+
+velocity = lsim((S*10^(gain/20))\1, voltage, time);