Pittsburgh Modular Microvolt 3900, Manual

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16. Function Generator
The function generator is a complex dual stage (attack/release) envelope generator with voltage controllable rise
(41) and fall(42) times. The cycle button(39) retriggers the function generator at the end of the fall stage to create
a voltage controlled low frequency oscillator.
When used as a low frequency oscillator, the rise slider(38) sets the length of the rise of the waveform and the
fall slider(40) sets the length of the fall of the waveform. The function generator modulation input jack(132) can
be used to control the frequency of the LFO. The rise and fall modulation trimmers (41 and 42) can be used to
control the symmetry of the modulation.
The input of the function generator is internally patched to the output of the midi gate jack(106). If you do not
want the midi gate to trigger the function generator, plug a patch cable in the input jack(133) of the function
generator to break the internal connection to the midi gate output.
The output jack(134) of the function generator is internally patched to the frequency modulation input jack(120) of
the binary filter.
Function Generator Patching Notes
•
An interesting low - fi filter sound can be created by setting the function generator to cycle as quickly as
possible and adjusting the binary filter frequency modulation trimmer(17). Take the sound one step further
by patching the midi pitch output jack(104) into the function generator modulation input jack(132) and set the
rise modulation and fall modulation trimmers full left. This allows the rate of the rise and fall to change with
the midi note.
•
The function generator makes a great voltage controlled LFO for audio rate modulation of the voltage
controlled oscillator.