There is basic FFT analysis built into the libraries that ship with LabVIEW Full Development System (FDS). However I would recommend considering the Sound & Vibration toolkit as an add on for LabVIEW. This contains more complete FFT analysis solutions (including averaged FFT analysers) and has a complete range of octave analysis (full and fractional analysis).
The examples are very good and even if you haven't had much experience of using traditional boxed FFT/octave analysers you will quickly be in a position to have a good working application up and running.
This brings me onto the question of the board that you are using. Depending on the type of signals that you are working with, you may find that there are a number of limitations to using the Lab-PC-1200.
1. The board has only 12-bit ADCs which therefore gives a maximum dynamic range of approx 72dB. A 16-bit board would offer a wider dynamic range of 96dB while some of the dedicate signal/audio analyser boards on offer from NI have 24-bit ADCs and a dynamic range of 120dB.
2. If you are analysing more than one channel and are looking at phase measurements (i.e. stereo if it is audio you are acquiring) you will be limited by the architecture of the Lab-PC-1200. This board uses a multiplexer to switch from one channel to another. This will automatically insert a phase error into the measurements that you take. An example of where this might be a problem would be if you were analysing the response from two audio speakers, or trying to analyse the performace of an object to vibration using multiple accelerometers. Dedicated boards on offer from NI (NI 44xx range) have simultaneous sampling inputs and these get around these phase problems.
The analysis that you perform with such a board all takes places on the host computer i.e. your Windows PC. As such you comment "is it possible to apply, in real time..." will depend entirely on the specification of your PC. NI does offer a few boards that will allow FFT and octave analysis to be performed on the actual DAQ board itself (NI 45xx range of dynamic signal analysers).
So in summary, consider the Sound & Vibration toolkit and also consider the limitations of the Lab-PC-1200. It may not be the best choose - but if you are stuck with the board, you can still develop a suitable LabVIEW application and if possible upgrade the hardware sometime in the future (the code should not need to change if you change the board).
Jeremy
