Reworked the analysis for the Ty stage motion

src/index.org

@@ -36,6 +36,10 @@ This Matlab function is accessible [[file:voltageToVelocityL22.m][here]].
   S = S0*(s/2/pi/f0)/(1+s/2/pi/f0);
 #+end_src
 
+#+begin_src matlab
+  voltage = detrend(voltage);
+#+end_src
+
 #+begin_src matlab
   velocity = lsim((S*10^(gain/20))\1, voltage, time);
 #+end_src
@@ -70,9 +74,128 @@ This Matlab function is accessible [[file:voltageToDisplacementL22.m][here]].
 #+end_src
 
 #+begin_src matlab
-  voltage = voltage - mean(voltage);
-
   velocity = voltageToVelocityL22(voltage, time, gain);
 
   disp = lsim(1/s, velocity, time);
 #+end_src
+* getGroundVelocity
+  :PROPERTIES:
+  :header-args:matlab+: :tangle getGroundVelocity.m
+  :header-args:matlab+: :comments org :mkdirp yes
+  :header-args:matlab+: :eval no :results none
+  :END:
+  <<sec:getGroundVelocity>>
+
+This Matlab function is accessible [[file:getGroundVelocity.m][here]].
+
+#+begin_src matlab
+  function [time, velocity] = getGroundVelocity()
+  % getGroundVelocity -
+  %
+  % Syntax: [time, velocity] = voltageToVelocityL22()
+  %
+  % Inputs:
+  %    -  -
+  %
+  % Outputs:
+  %    - time - in [s]
+  %    - velocity - in [m/s]
+
+    current_dir = pwd;
+
+    src_dir = mfilename('fullpath');
+    src_dir = strsplit(src_dir, '/');
+    src_dir = strjoin(src_dir(1:end-1), '/');
+    cd(src_dir);
+
+    data = load('mat/data_028.mat', 'data'); data = data.data;
+    time = data(:, 3);
+
+    [velocity] = voltageToVelocityL22(data(:, 1), time, 60);
+
+    cd(current_dir);
+  end
+#+end_src
+
+* getGroundDisplacement
+  :PROPERTIES:
+  :header-args:matlab+: :tangle getGroundDisplacement.m
+  :header-args:matlab+: :comments org :mkdirp yes
+  :header-args:matlab+: :eval no :results none
+  :END:
+  <<sec:getGroundDisplacement>>
+
+This Matlab function is accessible [[file:getGroundDisplacement.m][here]].
+
+#+begin_src matlab
+  function [time, displacement] = getGroundDisplacement()
+  % getGroundDisplacement -
+  %
+  % Syntax: [time, displacement] = voltageToVelocityL22()
+  %
+  % Inputs:
+  %    -  -
+  %
+  % Outputs:
+  %    - time - in [s]
+  %    - displacement - in [m]
+    s = zpk('s');
+
+    [time, velocity] = getGroundVelocity();
+
+    displacement = lsim(1/s, velocity, time);
+  end
+#+end_src
+
+* getPSDGroundVelocity
+  :PROPERTIES:
+  :header-args:matlab+: :tangle getPSDGroundVelocity.m
+  :header-args:matlab+: :comments org :mkdirp yes
+  :header-args:matlab+: :eval no :results none
+  :END:
+  <<sec:getPSDGroundVelocity>>
+
+This Matlab function is accessible [[file:getPSDGroundVelocity.m][here]].
+
+#+begin_src matlab
+  function [pxx, f] = getPSDGroundVelocity()
+  % getPSDGroundVelocity -
+  %
+  % Syntax: [pxx, f] = voltageToVelocityL22(in_data)
+  %
+  % Outputs:
+  %    - psd -
+  %    - f -
+
+  [time, velocity] = getGroundVelocity();
+
+  dt = time(2) - time(1);
+  Fs = 1/dt;
+  win = hanning(ceil(10*Fs));
+
+  [pxx, f] = pwelch(velocity, win, [], [], Fs);
+#+end_src
+* getPSDGroundDisplacement
+  :PROPERTIES:
+  :header-args:matlab+: :tangle getPSDGroundDisplacement.m
+  :header-args:matlab+: :comments org :mkdirp yes
+  :header-args:matlab+: :eval no :results none
+  :END:
+  <<sec:getPSDGroundDisplacement>>
+
+This Matlab function is accessible [[file:getPSDGroundDisplacement.m][here]].
+
+#+begin_src matlab
+  function [pxx, f] = getPSDGroundDisplacement()
+  % getPSDGroundDisplacement -
+  %
+  % Syntax: [pxx, f] = voltageToVelocityL22(in_data)
+  %
+  % Outputs:
+  %    - pxx -
+  %    - f -
+
+  [pxx, f] = getPSDGroundVelocity();
+
+  pxx = (sqrt(pxx)./(2*pi*f)).^2;
+#+end_src

src/voltageToDisplacementL22.m

@@ -13,8 +13,6 @@ function [disp] = voltageToDisplacementL22(voltage, time, gain)
 
 s = zpk('s');
 
-voltage = voltage - mean(voltage);
-
 velocity = voltageToVelocityL22(voltage, time, gain);
 
 disp = lsim(1/s, velocity, time);

src/voltageToVelocityL22.m

@@ -18,4 +18,6 @@ f0 = 2; % Cut-off frequnecy [Hz]
 
 S = S0*(s/2/pi/f0)/(1+s/2/pi/f0);
 
+voltage = detrend(voltage);
+
 velocity = lsim((S*10^(gain/20))\1, voltage, time);