Software Defined Radio with HackRF, Lesson 7

Complex Numbers in DSP

In order to clearly see my screen during the demonstration, viewing the video in full screen mode may help. Even better: You can download this video in high resolution (720p). (torrent)

in this lesson


  1. Launch GNU Radio Companion and locate the block called Quadrature Demod. This block implements the method for frequency demodulation presented in the video. Notice that it takes complex input and produces real-valued (float) output which is a sequence of angles.
  2. Can you find a block that implements our method of amplitude demodulation? It should take complex input and produce real-valued (float) output where each output sample is the magnitude of an input sample.



Software Defined Radio with HackRF is copyright 2014, 2015 by Michael Ossmann and is released under the CC BY license.