[Discuss-gnuradio] Doppler shift on waterfall plot with audio signal

[Steve Gough]

Hi All,

I am interested in analyzing the doppler shift of a transmitted signal.

As a first step, I want to see if I can capture hand movements in a Waterfall sink for an audio signal (tone). For that I use a flow graph like the attached screenshot based on https://github.com/ckuethe/gnuradio-examples/tree/master/doppler_sonar and https://www.youtube.com/watch?v=9trGfdcMPtk&noredirect=1.

I don't observe any doppler shift when I move my hand/walk in the vicinity. I can see the FFT plots change in shape on motion, but nothing is observed on the Waterfall sink.

Could you please tell me if I am missing something here?

The observed waterfall spectrogram is also attached.

Thanks,

Steve

flowgraph_doppler.png
Description: PNG image

observed_plots.png
Description: PNG image