Transfer Function from Poles and Zeroes

Build a transfer function out of a collection of poles (in red) and zeroes (in blue) in the complex plane. When poles and zeroes are complex conjugates, the amplitude of the transfer function is symmetric and the phase is antisymmetric, which corresponds to a real impulse response. Otherwise, the impulse response is complex.

Transfer Function from Poles and Zeroes from the Wolfram Demonstrations Project by Philippe Thévenaz