In the second exercise we will use again the graphical programming environment called LTPDA Workbench. After checking that the workbench is loaded, let's go ahead an create a new pipeline, or analysis diagram.

Let's use the command "Pipeline -> Rename Pipeline" to give this diagram a more significant name, such for instance "LTPDA Training Session PSD2".

The idea of the second exercise is the following:

  1. load a list of time-series with noise data from disk
  2. evaluate the Power Spectrum of the different data sets and:
  3. plot the results in different plot styles
In a flow diagram, the representation is as follows:

Dataflow for the 2nd example of ao/psd

Loading experimental data time-series from data files

This step was touche aupon in previous steps and in the user manual (see for instance xxx or yyy). Here we proceed using the ao constructor mehthod/block, that we can retrieve from the library or with the "quick block" shortcut.

We give the block a sensible name by double-clicking on it, and then we proceed with setting the parameters as follows:

Let's first choose, from the "Parameters" drop-down list, the "From ASCII File" set, and hit "Set" to assign this choice to the currently selected ao constructor block.

We can now tune the key parameters of the ao constructor: in particular, let's double click on the first parameter line, within the "Value" colum, so we can choose "noise" from the drop-down list that will appear. If needed, more help can be found here.
Key Value Description

FILENAME

'blah_x1.dat'

The name of the file to read the data from.

TYPE

'tsdata'

Interpret the data in the file as time-series data.

COLUMNS

[1 2]

Load the data x-y pairs from columns 1 (as x) and 2 (as y).

XUNITS

's'

Set the units of the x-data to seconds (s).

YUNITS

'V'

Set the units of the y-data to Volts (V).

ROBUST

'no'

Use fast data reading for this simple file format.

DESCRIPTION

'IS1 FEE x1 data'

Set some text to the 'description' field of the AO.

This procedure can be repeated for all 4 channels we want to analyze