Moog Prodigy
The Moog Prodigy has a nice sync feature that syncs both oscillators and frees up the pitch wheel to do something cool. The service manual says the sync switch locks the fundamental frequency of oscillator 2 to oscillator 1 and “disconnects the pitch wheel from U11A (osc 1 & 2 pitch bend) and routes it directly to transistor Q7 of U3A (osc 2 freq mod). Therefore, the pitch wheel shifts the upper harmonics of oscillator 2”
I recorded the effect on a scope at high and low frequencies while adjusting the filter along the way. Apologies for the low quality.