The Noise Engineering Cursus Iteritas is an oscillator that works from a dynamically generated wavetable. It gives the user spectral-like controls over three different modes based on different conceptualizations of frequency: Fourier, which uses sine waves; Daubechies, using wavelets, and Walsh mode, using the Walsh transform.
Center, Width, Tilt & Structure determine amplitudes for each harmonic. This description is fed into the inverse transform for the current function, set to produce the time-domain wavetable. The wavetable is normalized to reduce amplitude variations across spectral changes. The Edge control oversampling interpolation, with any additional aliasing being largely harmonic in nature. In many places in the signal path, there are soft clipping stages to mimic analog-style clipping to give more warmth and complexity to the sounds generated.
All knobs on Cursus Iteritas function as offsets for the input jacks. The controls function similar to a bandpass filter; center, width, and tilt allow the filter to be asymmetric.
- Pitch – 1v/8va pitch control. For more control, see Range below.
- Center – selects the center harmonic used to build the wavetable.
- Structure – allows selection of harmonics included in the output. In the center position, all harmonics are included. Fully left only even harmonics; fully right, only odd.
- Edge – controls the oversampling filter of the wavetable. As this is turned to the right, it will add musical overtones.
- Fold – wavefolder. Enough said.
- Width – controls how many different harmonics are used to create the wavetable. Tilt weights the spread of harmonics. In the middle it is symmetric; at left, lower harmonics are louder while at right, higher harmonics get more volume.
- Sync – triggers edge-based oscillator reset
- Mode – selects which orthogonal function set is used to produce the wavetable
- Range – two-octave offset pitch ranges
- Out – audio output – 10vpp
Power: A jumper selects using +5V from the power supply, or generating +5V on-board from the +12V rail.
With external 5v selected: 80mA @ +12v / 5mA @ -12v / 90mA @ +5v
With internal 5v selected : 150mA @ +12v / 5mA @ -12v / 0mA @ +5v