Cross-modulation/sync
In a common-or-garden ramp-based analogue VCO, oscillator sync works by resetting the ramp
integrator based on the frequency of the syncing signal. Lorelei works quite diferently, though
similar efects can be obtained. In Lorelei, the sync input essentially prevents the oscillator from
oscillating when the input is above a certain voltage (around 3.3V), but this is not an on-of thing
– the efect gradually applies as the voltage increases. The upshot of this is that smooth
waveforms (e.g. sine or triangle) for the syncing input produce a diferent efect to, say, square
or pulse waveforms. Also, when using a pulse wave as the sync input, the pulsewidth of the
signal also afects the result quite drastically. In the examples below, Lorelei's output is at the
top (in green) and the sync input waveform is at the bottom (in magenta).
Sync from
±
5V sine wave:
Sync from
±
5V triangle wave:
