A reader of our blog has recently written in to let us know about a lab sheet from the University of Colorado College of Engineering and Applied Science which clearly explains software defined radio theory with the aide of an RTL-SDR dongle.
The lab sheet starts off by showing how the RTL-SDR works at a high level, then goes on to explain the function of the R820T tuner chip and RTL2832U chip. The lab then shows a behavioural level model of the RTL-SDR which becomes useful for mathematical analysis. Finally, the lab also explains demodulation theory for FM and FSK signals and sets several lab exercises that involve writing FM and FSK demodulators in MATLAB or Python.
The zip files mentioned in the lab sheet can be downloaded from http://www.eas.uccs.edu/wickert/ece4670/lecture_notes/.