As orthogonality is an important characteristic in LoRaWAN but most public references just make a conclusion that different SFs are orthogonal. This confused me a lot and hope to make a clear understanding.
As @Chris Stratton show me in the link http://www.sghoslya.com/p/lora_6.html, I can tell different signal from different SF and BW combination. But I still feel there's a gap that why this suggest orthogonal?
And the frequency-time figure is not the common frequency-amplitude figure that shows signal in frequency domain after Fourier Transformation. How this frequency-time figure used in real signal processing step? Also, in https://lab.dsst.io/slides/33c3/7945.html, the author suggested in page 80-83 the demodulation of LoRa. It leaves me the question that why up-chirp multiples the down-chirp result in a constant frequency?
Thanks for @Neil_UK's kind suggestion: )