In this work, the modulated optical signals of different choppers used in IR seekers have been studied and analyzed.The aerial hot targets are sources of IR radiations due to the heat of their engines and the aerodynamic friction heat of their surfaces. The optical parts of the homing head target seeker collect the optical radiations from the target and from the background, and then focus them as a spot on a chopper used to modulate these radiations. These choppers are different in shape used to realize different types of optical modulations, in order to determine the target polar coordinates in the space and suppress the background radiations. The practical part of this work included the design of a special mechanical stend to rotate different choppers with different angular velocities allowing the focused radiations to pass through the chopper toward the detector. The mechanical stend also designed to move the target spot horizontally and vertically. The output electrical signals from the chopper circuit are modulated in amplitude, frequency, and pulse-width. 89C52 microcontroller has been used to determine the target polar coordinates.