From Florian Anwander Sent Sun, Apr 22nd 2018, 19:32
Hello short version: A trigger describes a time stamp, a gate describes a duration between two timestamps. long version: A trigger is NOT(!!!) a short pulse. A trigger is the transition between to levels of voltage. And in detail: it is the moment when the changing voltage passes a dedicated voltage level (the so called threshold voltage). There are two kinds of triggers: positive and negative. We speak about a positive trigger, when a the transition is from a low level to a high level. And we speak about a negative trigger, when the transition is from a high level to a low level. So in fact a gate defines the duration between a positive trigger (usually=note on) and a negative trigger (note off). see: http://fa.utfs.org/diy/Trigger_vs_Gate.jpg For a trigger it does not matter whether the transition in the relevant direction is immediate or not, and it does not matter, how the change back looks like see: http://fa.utfs.org/diy/Trigger_vs_Gate_2.jpg left graph. It is nive to know that a saw-like signal my trigger more safely than a pulse, because a pulse thends to overshoot and to swing back. This can cause doubletriggering (in the graphics the position [b] is the correct trigger timestamp, and the position [c] is the unwanted double-trigger caused by the overshoot of the negative slope of the "trigger"-signal. Of oourse when there is transition from low to high (= a positive trigger) there must come the day, when we go back from high to low. So every trigger signal is in fact a kind of gate signal. But the trick is: whether the signal is recognized as gate (event with duration) or as trigger, decides the receiver(!). There are receiver-functions in a synth, which recognize only the positive transition (=the positive trigger). For example an AD-envelope, which starts an the positive ramp and does its increase/decreas run - no matter what happens else at the trigger-input. And there are receiver-functions, which use the positive transition to start an event and the negative tranistion to recognize the duration of the event. For example an ADSR, which starts the attack phase with the positive transition, then does the decay and holds at the sustain level and would stay there until the end of times if here wouldn't be a negative trigger, which says: do "release" now. I hope this clears the confusion about the two terms "Trigger" and "Gate". Florian