[Duplicate] ES16 - Extended ADSR

ADSR

In addition to the usual Attack, Decay, Sustain, Release envelope, it has an adjustable delay at the beginning of the envelope. All timings and the Sustain level can be voltage controlled. The envelope can be linear or exponential, or linear with an exponential attack. There is also a master CV input that allows all timings to be reduced at once. When controlled by the same voltage as being used for VCO pitch, this allows for shorter envelopes for higher frequencies, as happens in acoustic instruments.
Note that this design is a little unusual in that the Gate input will sit at "ON" when nothing is connected to its jack.

http://www.elby-designs.com/contents/en-us/p974_ES16_-_Extended_ADSR.html