'Getting Started with LabVIEW'

Bianca and I went over essentially what she wants me to do. There is no THz setup to experiment with for now, but plenty of data to process and convert into a more clear and tangible form. And that is what I will be accomplishing during my stay here.

Like I described in my previous post, the THz setup signals ultimately take an electrical form like voltage or current before they reach a computer. Each collected data point is assigned a voltage amplitude and time for example. These points can be manipulated to reveal a whole lot of Time Domain Spectroscopy (TDS) information. But first getting the time sampling into a waveform can be very useful and better all around if you want to progress into spectroscopic evaluation. And all this can be done through LabView.

LabVIEW is a software package that enables its users to work with 'virtual instruments'. With this software you drag, drop, and define function and control blocks the way you would type and arrange code for a MatLab mfile in order to execute a program. Not only are these blocks time saving and easier to visualize, they also include many signal processing functions.

LabView Front Panel and Block Diagram screen shot (I recommend clicking on it to enlarge the figure)

Two major windows you can work with are the block diagram window and front panel. The front panel (gray background) serves as the interface for the user. Here data is displayed and saved. The block diagram (white background) is where all the dirty work happens. Blocks can be added and arranged as needed, and display desired features on the front panel.

The plan is to create a front panel that is easy to navigate and allows the user to look at time sampling files (simultaneously if desired) of either .txt, NASA software, or .picotd files. The output will be in graphical form that can be inspected by the user. Data from the selected sections of the graph, which I'll call Regions of Interest, will be displayed by a table. There are certain things to note when working with these different file types:

• .txt : Have no headers to work with. Data appears in two columns (1: time, 2: Amp). Time increment, Δt, between measurements is determined by [t_2 - t_1].
• Nasa : Are text files but with one column of data (Amp). Must know time sampling window (80 ps or 320 ps) and total data points. Δt is equal to [sampling window time/total # of data points].
• .picotd : Contain two columns of data like .txt, but contain headers that are ~185 characters long. A special block that skips over characters must be added to the diagram. Δt can be found following the same procedure for .txt files.

The user will be prompted to specify the file type and then LabVIEW will know what path to direct towards.Front panel scheme for a single .txt file

For now I am starting small and will develop a simple program with one .txt data file. From there I will develop programs for NASA and .picotd files.

Here's to programming!