The Realiation Of ATP In The System Of FSO

Free Space Optical Communications (FSO for short) is a new medium of solving the "Last One Millimeter" problem existing in the wideband network. The Acquisition, Tracking, and Pointing (ATP for short) system, which mainly consists of the Position Sensitive Detector (PSD for short), the single-chip computer, and the Piezoelectric Ceramic, is the key of the FSO.The PSD is a new type of photoelectric detector based on the lateral photoeffect. It can give the continuous position data corresponding to the incident spot on its photosensitive surface and can come into being the position error signals in ATP system. In practice, in order to assure the exactness of the output position, the background light's influence must be eliminated.The single-chip computer control circuit converts the output signals from PSD into the drive voltage signals of the Piezoelectric Ceramic. It focuses on the single-chip computer, along with the A/D converter and D/A converter that will connect previous and forward circuits.My graduate paper introduces the concepts of the FSO, the practical principles of PSD, the methods of eliminating the background light's influence, and the principles of A/D converter, D/A converter. Based on all above, I design a useful circuit to distill the position error and a single-chip computer control circuit.