| br>A sub-oscillator is typically a digital 'flip-flop' circuit - push once for on, push again for off - which will divide any incoming control signal by two. It doesn't oscillate as such, so no need for voltage offsets, but simply responds to the master VCO's signal coming into it.
The ASV's sub is a little clever in that it generates square, sawtooth and triangle waves, although only the triangle is made available to the user.
There was no space to include a sub on the DVCO module. But a dedicated and more comprehensive sub oscillator module is planned for the future. It may even end up as a 5U module too.
Tony br> br>