User Manual

13
Oscillators
The Oscillators section contains the primary controls for Mopho’s two digitally
controlled analog oscillators or DCOs. “Digitally controlled” does not mean the
oscillators themselves are digital, just that the oscillators’ frequencies are under
digital—rather than voltage—control. The advantage to that is that the tuning is
exceptionally stable over a ten-octave range without having to compensate for
variables like temperature. The audio signal path is still completely analog.
Oscillator Select—Choose oscillator 1, oscillator 2, of both. When both 1 and 2
are selected, changes made to the other oscillator parameters affect both
oscillators.
Frequency: C 0…C 10—Sets the base oscillator frequency over a 10 octave
range, from 8 Hz to 8KHz, stepping in semitones. C3 is middle C, the first
octave is 0 (C0, C#0, etc.), the second octave is 1 (C1, C#1, etc.), and so on.
Fine Frequency: -50…+50—Fine tune control with a range of a quartertone up
or down. Zero is centered. Steps are in cents (50 cents = 1/2 semitone).
Shape Select: Sawtooth, Triangle, Saw-Tri, Square, Off—Selects the oscillator
waveshape. If none of the shapes are lighted, the oscillator is off.
Pulse Width: 0...99—Sets the pulse width or duty cycle of the square wave. A
value of 50 results in a true square wave with equal alternating high and low
levels. Increasing or decreasing the value from 50 causes the waveshape to
become asymetrical. Lower values narrow the postive-going portion of the
Sawtooth
Triangle
Saw-Triangle
Square