3 ms·

I guess it's like time running backwards. Or the speed. FM is basically turning the speed up and down, no reason it can't go backwards too! Edit: or a DJ doing

I guess it's like time running backwards. Or the speed. FM is basically turning the speed up and down, no reason it can't go backwards too! Edit: or a DJ doing a record scratch

gylterud 3y ago
Yes, this is precisely the intuition I have. The oscillator is running through a waveform with a speed corresponding to its frequency. Frequency modulation speeds it up or slows it down. At negative frequency it goes backwards. With symmetric TZFM it spends as much time going backwards as going forwards, and does so in audio rate giving a folding of the modulation signal.