281e contains four identical function generators, an external pulse activates the attack-decay cycle. After the cycle is completed, the pulse is available at the output.
Three operating modes are available for each generator:
/// - in this mode the unit enters the self-generation and that’s how you get an LFO. In this case, the knobs of the attack and decay regulate both the waveform and the frequency.
/ - attack-release envelope mode, while the duration of the applied pulse is not taken into account.
/ ˉ - the envelope of the format attack-sustain-release. The duration of the applied pulse determines the release time.
In the "quadrature" mode, the function generators work in pairs. In this case, only the input of the first generator in the pair is used.
The second generator gets started after the end of the attack period of the first one.
For oscillator pairs, the "or" mode is also available, in which the output signals of the function generators are controlled.