Thanks, I found this to be very useful! I&#x27;ve been trying to learn about physical layer networking and been reading a communication systems textbook (the one by Haykin), and being able to visualize the different transformations on signals was super useful.<p>The section on FIR, IIR, and how to make high-pass and low-pass filters was also useful to me. I have a decent math background, so I&#x27;m finding one of the hardest parts of working through an intro communications textbook is figuring out the EE jargon (in-phase and quadrature, narrowband and wideband, etc).