IMPLEMENTATION OF OFFSET PULSE POSITION MODULATION using ALTERA

Optical fibre systems have played a key role in making possible the extraordinary growth in world-wide communications that has occurred in the last 25 years, and are vital in enabling the proliferating use of the Internet. Its high bandwidth capabilities. low attenuation characteristics. low cost. and immunity from the many disturbances that can afflict electrical wires and wireless communication links make it ideal for gigabit transmission and a major building block in the telecommunication infrastructure. The main concern of this project is investigation and implementation of the Offset Pulse Position Modulation (Offset PPM) communication system. Novel work is carried out for applying Offset PPM over an optical communication channel theoretically and experimentally to examine the system performance. An Offset PPM encoder and decoder will be implemented to code Pulse Code Modulation (PCM) format into Offset PPM format and to decode back the Offset PPM to PCM. A further investigation took place on the Offset PPM associated output. Computer programming and simulation using the VHSIC Hardware Description Language (VHDL) of this PPM code Should be considered and comparison with previous theoretical results. The received Offset PPM signal should returned back to its original input PCM form without errors. Successful VHDL and Field Programmable Gate Array (FPGA) implementation using Altera Quartos II amd Modelsim of Offset PPM encoder and decoder as a single system should be presented in the study. An FPGA embedded Bit Error Rate (BER) test device should also be implemented for sensitivity measurements purposes and all the designs have been tested successfully with back-to-back testing. An optical communication system (transmitter/receiver) over POF should be developed and the Offset PPM scheme will investigate through this optical channel.