Analogue Filters Modeling and Simulation

Purpose

Analog filters such as low-pass, high-pass, etc. can be modeled and simulated using a variety of techniques and tools. This blog reviews some of these techniques. Although the theory behind analog filters has been known for a long time, it's a good idea to have a quick look at the equations that characterize them, as a sort of memo. This is what I propose to do on this blog, by presenting the most well-known filters, with a lot of examples showing how to model and simulate them.

Remark: z-filters are not covered.

Contents

• Theory reminder
• Different kind of analysis
• Laplace transfer functions
• Differential equations (ODE)
• State Space Modeling (SSM)
• Recurrence equations approach
• Simulation principles
• Examples
• Application to audio amplifier

Examples are given with the following software tools :

• EXCEL
• MATHCAD
• SCILAB
• XCOS
• MATLAB
• SIMULINK
• PYTHON
• MATHEMATICA
• MAPLE
• LTSPICE
• OPENMODELICA