Last week, I fell into the rabbit hole of "negative frequency". Is it just a quirk of the maths or a real-world phenomenon?
I wanted to recommend Mark Newman's enjoyable and brief "negative frequency" introduction video. Mark brings together some complex ideas into layman's terms that even a beginning hobbyist can understand.
The video clarified some tough concepts and his nifty 3-D diagrams were self-explanatory. The video briefly touches on: music, trigonometry, Fourier transform, AM/FM radio signals, sidebands, etc.
Mark is an electronics engineer who recently published the book, "How the Fourier Transform Works". He also has a great "Circle of Fifths" introduction video for aspiring musicians.