A-140 ADSR Envelope Generator
Module A-140 is an envelope generator, and, since it puts out control voltages, counts as one of the modulation devices in a modular system. As soon as the gate input receives sufficient voltage, the ADSR generates a variable voltage, changing in time, called an envelope. This varying voltage is output in normal (positive) and inverted form, and can be used, eg., for voltage controlled modulation of a VCO, VCF, or VCA, or for processing other modules' inputs and outputs.
The shape of the envelope is governed by four parameters: Attack, Decay, Sustain and Release.
The envelope is started (triggered) by a gate signal either from the INT.GATE voltage on the system bus, or, if a signal is put into it, from the gate input socket.
The envelope can also be re-triggered, ie. start from scratch again, each time a trigger signal is sensed at the Retrig. input socket, when the gate is still open.
Module A-140 has available a three-position toggle switch to select one of three time ranges. The time ratios for the three ranges are about 1 : 20 : 1000. The absolute Attack times are about:
- 20uS ... 100ms (switch position L)
- 400uS ... 2s (switch position M)
- 20ms ... 120s (switch position H)
The Decay and Release times are about 3-4 times more. Because of the exponential slope and the gradual asymptotic approach to the zero level the exact specification of the decay and reales times is a bit difficult.
The voltage ranges of the ADSR outputs are about 0 ... +8V for the two normal outputs and 0 ... -8V for the inverted output.
In combination with the Comparator module A-167 a free-running "ADSR-LFO" can be realized.
For more detailed information please look at the English user's manual: A140_man.pdf.
Related modules are the 4-fold ADSR A-143-2, the voltage controlled ADSR A-141-2 and the voltage controlled Decay/Gate module A-142-1.