Periodic Examples

A rotary encoder is a sensor that mechanically attaches to a motor or drive shaft. A light sensor is shinned on a disk with slots so that pulses are generated. That's a lot of words for anybody reading not familiar with these things... I('m going to add pictures(soon).

The point is: Something is spinning at a frequency, for simplicity lets start off by saying a fixed frequency. There are different plotting domains and most people are familiar with "Cartesian, x-y graph". The complex number plane is essentially the same thing as the x-y graph but replace "x" with real(r) and "y" with imaginary(i) (It's not complex as in geometrically complicated). Read to the Complex Plane