TFilter, the free online FIR filter design tool - Free online IIR Filter Design Tool, Filter Testbench, FFT library and scripting environment at http://almafa.org/docs/iir.html. For more information visit http://almafa.org/. | Facebook
An Astounding Digital Filter Design Application - Rick Lyons
Filter Design HDL Coder - MATLAB
Introduction to IIR Filters - Circuit Cellar
Digital Filter Design - MIKROE
FIR Filter tools
ScopeIIR: IIR Filter Design Software - Iowegian International
Digital filter design and analysis - LabDeck
Design and implement digital FIR and IIR filters - Simulink