It contains four separate attack/decay type envelope generators.
The four units can be used even as four separate AD generators (mode switch in position AD) or free-running AD type LFOs (mode switch in position LFO).
Each unit has available a comparator that compares the AD output voltage against a manually adjustable threshold and turns on the corresponding comparator
output as soon as the AD output voltage goes below the threshold level during the decay phase.
The comparator outputs are normalled to the trigger inputs of the following stage via the switching contacts of the trigger input sockets.
Consequently the first unit triggers the second, the second triggers the third and so on (and the last unit triggers the first one).
Each AD/LFO unit also offers a polarizer control.
This allows adding/subtracting or offsetting (depending on bottom right switch selection) all AD/LFO signals to the mix output with adjustable level.
Additionally each unit features a single envelope output and a digital “End Of Attack (EOA)” output, that indicates the end of the attack phase.
The threshold setting defines the behaviour of the Comparator output (Cp Out).
This output turns “low” as soon as the level of the envelope signal exceeds the threshold level. Otherwise it’s high.
During the rising slope of the envelope (attack phase) the envelope cannot be retriggered or reset.
And during the falling slope (decay phase) the direction changes if a trigger signal appears (changes from decay to attack state).
If the unit in question is used as an LFO, a dummy cable or jack plug can be patched into trigger socket or you can activate the proper switch at the bottom left.
Otherwise the LFO is retriggered by the comparator output Cp of the preceding unit because of the normalling of the trigger socket.