FFT Web is an Out-Of-Tree block which sends a signal FFT by UDP to a websocket server. This websocket server packs and broadcast this FFT data to websockets, which can be opened by html/javascript code for real-time display of the fft in web-browsers (don't worry we are already providing that part ;) ).

FFT Web block come along with the CorteXlab OOT module, but it can also be found on github.

FFT web is a FFT sink block you have to feed with the signal you want to analyse. for example you can put it just ater an USRP Source block to act as a spectrum analyser.

FFT Web can be tune with several parameters :

• fft_size The size of the FFT ( 256 is a good start)
• power max The upper limit of the measured power in dB (-30 is a good start)
• power min The lower limit of the measured power in dB (-100 is a good start)
• port The port use to send the data. Usefull when you are using multiple fft web block. (default is 6663)
• frame rate The frequency of the acquisition (10 is a good start)
• samp rate This correspond to the bandwith of the signal
• ip address The address of the websocket server the data will be sent to. The address of our server is “srvwww.cortexlab.fr”.

The resolution of graphic will be samp rate/fft size.