FFT Filtering

This immersion provides an introduction to active feedback control of dynamical systems. Engineers typically cover this material in a semester- or year-long course, but the essence of the subject can be learned in a much shorter time by the motivated physicist. Necessary background material, including Fast Fourier Transforms and active filtering, will be covered first, followed by the basics of frequency-domain feedback control. The Immersion culminates with an example of noise suppression using active feedback, and an examination of the resulting signal in frequency space compared with the theoretical prediction. This immersion follows the method developed by the Laser Interferometer Gravitational-wave Observatory (LIGO) for giving physicists a crash course in frequency-domain feedback control.