I recently came to the conclusion that I should learn something more about signal processing and started reading the first pages of both Andy Farnell tutorials and Synth Secrets by Gordon Reid.
The basics of Amplitude Modulation seem clear to me. When multipling an oscillator signal (the carrier) for another one (the modulator), I get a new waveform which includes three frequencies: the carrier, the sum (carrier + modulator) and the difference (carrier - modulator).
It works fine, but something goes wrong when trying to make a reverse test. I am expecting that if I sum up three oscillators (carrier frequency, sum frequency, difference frequency) the resulting wave should sound like the one I get from the amplitude modulation, but it doesn't. It is the same (and the waveform correspond as well) only if I mute the carrier frequency. Why is this happening?
As a total beginner I'm pretty sure I'm missing some simple logic here. Attached is a test patch.
Thanks in advance for your patience.