"Signal Generator" is vintage Korg language for an oscillator. It includes the following standard analog synth oscillator controls:
Wave Form- Incorrectly bisected just like the real thing. This selects from the following oscillator waveforms: triangle, saw, rectangle (i.e. square), two preset pulse waves (with different widths), and PWM (variable-width pulse).
PWM Intensity (MG2 or Ext)- PWM is short for "pulse-width modulation". When Wave Form is set to the PWM position, the PWM Intensity knob sets the width or "duty-cycle" of the pulse wave. By default, Modulation Generator 2 (MG2 at the bottom-right of the panel) is normalled to PWM; the PWM Intensity knob sets the amount of modulation received from MG2. This adds timbral animation and a slight chorusing effect.
Other PS-3300 control signals, such as an alternate modulation generator, the Master Panel General Envelope Generator, Sample & Hold, etc. will override the default MG2 routing when a cable is plugged into the Ext PWM Control jack.
The MG2>PWM routing can be overridden to create a constant, non-modulated pulse width by using one of the Control Voltage Processors in the Master Panel. Route a cable from the Control Voltage Processor Out 1 or Out 2 jack to the Ext PWM Control jack at the bottom of the Signal Generators section. Set PWM Intensity and Ext Intensity Control knobs to max. The CV Processors Limiter B knob can now be used to vary pulse-width.
Frequency- Detunes the oscillator by slightly over a fifth, up or down. This can be used to fatten up multiple oscillator patches by detuning a small amount, or for "building-in" a set interval. The panel markings say -5 to +5; we’re not exactly sure what that’s supposed to correlate to (maybe they ran out of "7" Letrasets when they were laying out the panel), but the pop-up tooltip will accurately display detune amount.
Scale- Coarsely sets the signal generator pitch range in octaves. These are at standard organ footage settings of 32', 16', 8', and 4'.
Frequency and Pulse Width Mod Controls and CV Jacks
Reverse switch- Enabling the Reverse slide switch inverts the polarity of both the hardwired Mod Generator 1 and Ext Freq Control signals.
On switch- The orange On slide switch enables frequency (pitch) mod when in the down position.
MG1 Intensity Control- Sets the amount of frequency mod from Mod Generator 1.
Ext Intensity Control- Sets the amount of frequency mod from the Ext Freq Control mod input jack when a source is patched.
Ext PWM Control- Allows an external control signal to modulate oscillator pulse width when the Wave Form selector is set to PWM. The amount of mod is set using the PWM Intensity knob beneath the Wave Form selector.