TBA120A ... remember it?

Well, at college back in the early 70's we learned all about FM demodulators. WoW! the maths involved was amazing, we talked about phasor diagrams and had to understand them. Adding / Subtracting signals, producing audio from a Frequency Modulated signals. Drawing graphs and diagrams. I remember doing this at night school with Mr Tudor our principles tutor at college. Enough to do your head in!!

Then in the late 70's along came the TBA120 or SN76660 FM demodulator chip!

What a wonderful device this was...forget the principles...stick a 455khz FM signal up it's a**e and audio came out the other end. Before long all televisions had a version of it fitted and got rid of loads of discrete components.

I used it myself in a few projects, especially my VHF / UHF Receiver, a little gem of an analogue silicon chip.

I still have all my notes from college all written in fountain pen and beautiful graphs and diagrams!