differentiate wifi and bluetooth signals given a spectrogram

Hello,

i have to utilyze the device adalm-pluto to recognize wifi and bluetooth signals given a spectrogram image: could you help me? I really dont know how to differentiate a wifi signal from a bluetooth one (or others signals) given the spectrogram from the PASSBAND SPECTRUM app (launched with "

Spectrum Analysis of Signals

" ).

Also how can I save the actual image of the spectrogram from the passband spectrum app? It seems like i can only save the spectrogram's data with the function

specTable = getSpectrumData(hSpectrum);

which returns me all the data from the spectrum and spectrogram but not the actual images of them.

Thank you in advance

Answer 1

[SANKALP DEV]

Hello Davide,

I understand that you are seeking assistance on how to differentiate between wifi and Bluetooth signal from a spectrogram image.

Since you have the spectrogram data from the app, you can recreate the spectrogram in MATLAB and distinguish between WiFi and Bluetooth signals using signal processing techniques.

You can use MATLAB’s ‘spectrogram’ function to recreate spectrogram using the raw data.

WiFi and Bluetooth signals have distinct characteristics. WiFi signals usually operate in the 2.4 GHz or 5 GHz frequency bands, while Bluetooth operates in the 2.4 GHz band.

Now to distinguish between WiFi and Bluetooth based on their frequency characteristics, you can follow these steps-

• Find the indices of frequencies within the specified WiFi and Bluetooth ranges.
• Compute the average power in the specified frequency ranges.
• Set a threshold for classifying WiFi and Bluetooth signals based on average power.
• Classify whether the signal is WiFi or Bluetooth based on whether the average power exceeds the specified threshold.
• Now you can save the spectrogram image to a specific format using MATLAB’s ‘saveas’ function.

To know more about ‘Spectrogram’ and ‘saveas’ function refer to following documentation-

• https://www.mathworks.com/help/signal/ref/spectrogram.html?s_tid=doc_ta#mw_f4f519e3-460d-4b89-9f3a-750703e33ea8
• https://www.mathworks.com/help/matlab/ref/saveas.html

I hope it helps.

Thanks, and regards,

Sankalp dev.