In the study of both continuous-time and discrete-time systems, the frequency response and its relationship to pole and zero locations in the s- and z-planes, respectively, are of fundamental importance.
This helpful video presents the mathematical link between poles and zero locations and the frequency response. At this site, click the Extra Videos tab and then click Pole-Zero Geometry Explained with Animation.
The video presents a case study, using simple first-order continuous and discrete-time systems. The video first sketches the expected result and then uses the downloadable apps PZ_Geom, PZ_Geom_S, and PZ_Tool to bring the mathematics to life with animation. Using the third app, PZ_Tool, you can get a particular frequency response by interactively placing poles and zeros.
The graphical user interface (GUI) apps are available for download under the GUI Applications tab.