VCO-1 is an Oscillator that generates sine, triangle, saw and square waveforms at its outputs.
You can tune the VCO using the FREQ and FINE knobs, FREQ is used to tune with less precisione than FINE, which allows a more granular control over tuning of the VCO.
Waveforms can be generated using a switch for digital model (DIGI) or analog model (ANLG). The difference is simple: Digital model will result in a “perfect” wave, almost mathematical (digital), while the analog model will mimic the imperfection of an anlog circuit, which is never 100% accurate.
As an example, a digital square wave will be really “squared”, while an analog square will look more “rounded” or approximated in its shape.
Tuning can be controlled by MIDI-CV or other Modulated signals (Sequcner Rows, LFOs) using the V/OCT input. (the tuning of the VCO will vary depending on the notes sent by a MIDI Keyboard, or Sequencer, or LFO…)
FM Input port, attenuated by the FM CV knob, regulates the amount of FM (Frequency Modulation) used to modulate the VCO.
Square Wave has a P.WIDTH control that modulates Pulsewidth. PWM can also be controlled using a CV signal on the PWM input port, attenuated by the PWM CV knob.