IQ and complex signals tutorial

[Christophe Seguinot]

Hi

Two months ago we had long discussions about why GNURadio was using complex signal, and what really is such a signal. 

We talked about 'spinning dancer' 'sampling the data twice', and using "dogs as local oscillators". It was obvious that we need some tutorial.

I'm glad to introduce a new tutorial trying to answer this basic but important subject  https://wiki.gnuradio.org/index.php/IQ_Complex_Tutorial

I was not able to cover the subject in 10 min, so I will not get the Noble price of education ( see Jeff long email from November the 3rd 2020) )

This tutorial should be considered as a draft, I can and want to improve it.

• I used as less maths as possible, but whatever you don't understand, whatever you feel is not comprehensible should be modified: just ask it on the forum.
• I included some flowgraph, as simple as possible. A s a consequence some simulation can be quite far from the real SDR world
  
• I feel  this tutorial is probably too long, however only 50% are needed to get the main aspect of IQ and complex signal.
• I must confess that my english is poor and weak so I would appreciate if someone could at least improve the text by "making it english".
  

Regards, Christophe