Technical Papers

Below are some technical papers that will hopefully contribute some knowledge and algorithms to the DSP community in general. This knowledge is placed in the public domain, but if you find any of it useful then please feel free to email us and let us know!

Non-linear Analog Modelling / Signal Processing

From Circuit To Code: Under the Hood of Analog Modelling

adc-2020-andrew-simper-circuit-to-code-slides.pdf – Slides from talk given at the Audio Developer Conference 2020
https://www.youtube.com/watch?v=eGcqomH6aAc – Video of the talk given at the Audio Developer Conference 2020

Dynamic Smoothing

DynamicSmoothing.pdf – Two Pole State Variable Filter with self adjusting cutoff to musically smooth low bit depth and/or noisey control signals

Linear Analog Modelling / Signal Processing

Trapezoidal integrated filters

OnePoleLinearLowPass.pdf – One Pole Low Pass Filter
SvfLinearTrapOptimised2.pdf – State Variable Filter
SkfLinearTrapOptimised2.pdf – Sallen Key Low Pass Filter
SVF-vs-DF1.pdf – Noise performance plots
SvfLinearTrapAllOutputs.pdf – State Variable Filter Simultaneous computation of all outputs

Sin only coefficient computation in state increment form for low noise and high accuracy

SvfLinearTrapezoidalSin.pdf – State Variable Filter with Sin only coefficient calculation
SkfLinearTrapezoidalSin.pdf – Sallen Key Filter with Sin only coefficient calculation

Input mixing multimode filters – individual inputs for low, band, and high

SvfInputMixing.pdf – State Variable Filter with Input mixing for low, band, and high
SkfInputMixing.pdf – Sallen Key Filter with Input mixing for low, band, and high

Matching of Forward Euler SVF to Trapezoidal SVF

SvfMatchingFeToTr.pdf – Matching the linear time invariant frequency response of a Forward Euler integrated SVF to that of the Trapezoidal one