A Simple Digital Model of the Diode-Based Ring-Modulator

Julian Parker
DAFx-2011 - Paris
The analog diode-based ring modulator has a distinctive sound quality compared to standard digital ring modulation, due to the non-linear behaviour of the diodes. It would be desirable to be able to recreate this sound in a digital context, for musical uses. However, the topology of the standard circuit for a diode-based ring modulator can make the process of modelling complex and potentially computationally heavy. In this work, we examine the behaviour of the standard diode ring modulator circuit, and propose a number of simplifications that maintain the important behaviour but are simpler to analyse. From these simplified circuits, we derive a simple and efficient digital model of the diode-based ring modulator based on a small network of static non-linearities. We propose a model for the non-linearities, along with parameterisations that allow the sound and behaviour to be modified dynamically for musical uses.
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