LoRa Chirp Spread sprectrum and USRP

[davarr76]

Hi,

I'm using a USRP 2920, and I would like to get the chirp spread spectrum of a LoRa Emitter (868MHz).

I have been looking for the examples with the USRP toolkit, but i didn't find one wich could get the sprectrum.

See the attached image, to understand what I need ....

PS : with the VI "niUSRP EX Spectral Monitoring (History).vi" I can get the sprectrum (Amplitude vs frequency), but what I need is frequency vs time

Thanks !

Regards,

David

[Chan82]

Hi David,

To measure the frequency vs time spectrum, you can use the STFT function in LabVIEW.

You can search the function on block diagram:

Signal processing --> Spectral --> STFT spectograms.vi

Also, you can find out how to use it from some LabVIEW examples. Please try to search examples by STFT keywords on NI Example Finder.

Thanks.

[davarr76]

Hi Chan82,

Thanks for your answer ! I have found an example with STFT (STFT spectrogram demo.vi), but now the difficulty will be to get datas from the USRP, and to use this function so I could see the specific chirp modulation ....

Regards,

David