The signal processing functions present in VEGA rely on the Frv analysis library developped in VIRGO. A default version of the library is provided with the VEGA sources but may be upgraded at any time.

The API of this library are not yet finalized but come very close to this point.

This library uses the FFTW (http://www.fftw.org) library for computing fft’s. The installation of FFTW is not difficult and described in the installation documents, i.e. INSTALL file in the distribution or "Installation of ROOT"

The sources and documentation of Frv may be found http://wwwlapp.in2p3.fr/virgo/FrameL/. We will just give an example to demonstrate the use of the library to make an FFT of a vector.

A structure FrvRFFT that holds the result of an fft transform of a frame vector FrVect is defined. The algorithm itself is build and called with FrvRFFTFor (0,frvect) as for example in (suppose vect is an FrVect) :

This will create a standard fft and apply it to the vector vect. On output, the fft structure contains the result of the processing in the form of FrVect’s that one can plot as usual :

For the amplitude part of the fft. Once the fft object is not needed anymore, the user should delete it with

Look at the example scrollspectrum.C in the tutorials.

More information will be added as soon as the Frv library gets a standard shape.