Alternative Complex oscillator design-overview.
This design has a multiple VCO arrangement, this allows for morphing between Sine, Ramp, Triangle and pulse, as well as phase modulation. There is wavefolding on the Sine and Triangle oscillator outputs. The fifth oscillator has no audio output and is used purely to phase modulate the first four oscillators.
The oscillator is fed to mutiple waveshapers which morphs bertween different waveshaping formulae. The waveshaping is based on the formula 5*sin(x/pi). The waveshaping is split into odd and even formulae with morphing between the two sections.
The prefab (SE V1.5 only) can be downloaded from here
Third party modules are required:
RH-Wshape2 Available from http://www.rhmodules.nl
ED Range Clipper https://www.elenadesign.eu/edm
ED Morph 1D
ED Text Entry
The Double Oscillator module.
Five standard stock oscillators are used to allow morphing between the waveforms. Foldback is only used on sine and triangle wave shapes as the ramp and pulse shapes tend not to be worth wavefolding.
The Sine 2 oscillator is used purely for Phase Modulation of the five audible oscillators.
The wavefolder.
This relies on the RH-Wshape module fo gradually fold the waveform back on iteslf when it reaches a certain level. The amount of wave folding is controlled by the VCA on the input stage.
Adjusting the CV range for better control.
The ED Range clipper is used in combination with the multipler module so that the useful range of the Fold control voltage falls within the usual 1 to 10 Volts, otherwise the control was shomehat “cramped” as the useful voltage range without this conversion fall between 7 and 10 Volts. Input 2 of the divider is set to 1.5. The Range clipper is set to a Minimum of 7 volts and a Maximum of 10 Volts and the Mode is set to clip.
The Odd and Even wave-shapers.
I’ll describe both of these together. They are both made up of six Waveshaper2B modules using the formula 5*sin(x/pi) as a starting point. The formula changes slightly for each sucessive waveshaper. The ED Morph1D module at the output allows for a smooth morph between each formula. Each formula affects the harmonic content of the output in a different manner. The formulae are listed in the table below.
Odd:
5*sin(x/π)
5*sin(x/π*3)
5*sin(x/π*5)
5*sin(x/π*7)
5*sin(x/π*9)
5*sin(x/π/11)
Even
5*sin(x/π)
5*sin(x/π*2)
5*sin(x/π*4)
5*sin(x/π*6)
5*sin(x/π*8)
5*sin(x/π*10)
The complete Complex VCO structure.
All the main control settings on the Complex VCO can be modulated usin a CV within the range 0 to 10 V. The Scope3 module is optional, I just include it so the effects of changing control settings can be seen.
There is a Sync connection so that the oscillators can be synchronized to a single source, this could be connected to the output of another oscillator, or to the keyboard trigger plug on MIDItoCV to ensure phasing between oscillators is always constant.
