The AION 921 VCO is a variable waveform generator which produces frequencies ranging from sub-audio (LFO) to 40.000 hz. Four waveforms are available: sine, triangular, sawtooth and rectangular (with variable duty cycle A.K.A. pulse width modulation).
Both fixed and variable levels can be obtained from the front panel output jacks. Nominal frequency and range controls (octave) are found at the top of the module.

Voltage controlled rectangular width (VC-PWM) is set by the knob in the upper center (left) with the accompanying voltage input jacks.
Multiple frequency control inputs 1 and 2 can be plugged into this module in parallel. Control input 3 is used via the pot for linear frequency response (Liniar FM). All waveform outputs can be used if desired.

This is what we consider an improved version of the Moog 921 VCO, not a direct clone. Improvements were made concerning tuning and stability issues.

Frequency range:
0.01 hz - 40.000 hz

Range switch:
sub audio - 0.01 - 400 hz
audio - 1 - 40.000 hz

Scale switch:
2 or 12 octave frequency span.

Auxiliary outputs:
2 jacks (one normal, one inverted) with selected waveforms (sine, triangle, sawtooth, inverted sawtooth rectangular and inverted rectangular).
Waveforms amplitude controllable from 0 to maximum.

Hard and Soft synchronisation selectable via a switch.
Synch must be "OFF" (center position) when synchronisation is not beeing used, otherwise it will sound out of tuning.

Specifications:
Depth: 40mm
Doepfer compatible.

30 mA +12V
30 mA -12V
0 mA 5V