The Study of Pulse Interval Modulation in Wireless Laser Communication System

摘要

This paper studies the Pulse Interval Modulation scheme for wireless laser communication between two nodes. This Pulse Interval Modulation (PIM) scheme is a modified version of the Pulse Position Modulation (PPM) data scheme and is intended for fast, low power and reliable wireless laser transmission with simple, minimum and low-cost hardware implementation. This paper tries to introduce one of the methods how to realize the PIM modulation by the use of microcontroller. At first, this technique can effectively improve the synchronization puzzles confronted during the process of modulation and demodulation. The second, the method can improve the coding efficiency of the laser communication system. The third, it could be integrated into one system by using PIC controlling mode. For the laser communicating system transmits data with computers via asynchronous series ports so that the demodulator can be made simple and cheap. At the end, the paper concludes the advantages for this implementation such as easier circuit design, more stable working reliability etc.