Analog modeling of a diode clipper (1): Circuits

This entry is part 1 of 5 in the series Analog modelling of a diode clipper

I’ve published a few years ago an emulation of the SD1 pedal, but haven’t touched analog modeling since. There are lots of different methods to model a circuit, and they all have different advantages and drawbacks. So I’ve decided to start from scratch again, using two different diode clippers, from the continuous equations to different numerical solutions in a series of blog posts here.

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Analog modeling of a diode clipper (2): Discretization

This entry is part 2 of 5 in the series Analog modelling of a diode clipper

Let’s start with the two equations we got from the last post and see what we can do with usual/academic tools to solve them (I will tackle nodal and ZDF tools later in this series).

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Analog modeling of a diode clipper (3a): Simulation

This entry is part 3a of 5 in the series Analog modelling of a diode clipper

Now that we have a few methods, let’s try to simulate them. For both circuits, I’ll use the forward Euler, then backward Euler and trapezoidal approximations, then I will show the results of changing the start estimate and then finish by the Newton Raphson optimization. I haven’t checked (yet?) algorithms that don’t use the derivative like the bisection or Brent algorithm.

All graphs are done with a x4 oversampling (although I also tried x8, x16 and x32).

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Analog modeling of a diode clipper (3b): Simulation

This entry is part 3b of 5 in the series Analog modelling of a diode clipper

Let’s dive directly inside the second diode clipper and follow exactly the same pattern.
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Analog modeling of a diode clipper (4): DK-method

This entry is part 4 of 5 in the series Analog modelling of a diode clipper

DK method is explained at large by David Ye in his thesis. It’s based around nodal analysis and was also extensively used by cytomic in his papers.

When analyzing a circuit form scratch, we need to replace all capacitors by an equivalent circuit and solve the equation with this modified circuit. Then, the equivalent currents need to be updated with the proper formula.
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