APON System Ont Study On Optimum Design Of Prototype Function Testing System

Recent years, as the increasing of the telecommunication broadband-service, the present access network can not meet the demand of its development. The Passive Optical Network based on Asynchronous Transfer Mode (APON), which incorporates the support ability of ATM's multiple services and multiple bit ratios and the PON's transparent broadband transfer ability, will become one of the ideal fiber access techniques that is economical and flexible.This dissertation is the summing-up of the design of examination system of ONTs in APON system, it aims at analyzing the examination system which is used to test the main functions of the ONTs. On the basis of the analysis of the primary system's deficiencies, this dissertation put forward a new improved design of the system and also gives a discussion to the design and implementation of the key technologies such as burst-mode receiving, burst-mode synchronizing, scrambling and parallel communictation. The design method of the new examination board is based on FPGA of Spartan-3 family, which has better performances, in this way, the hardware circuit as well as the design and simulation of PCB and the ultimate design are provided. On the basis of analyzing the primary system, the new one makes improvements on some functional models and adjusts to the new hardware design. At last, and the debugging methods, steps of examination system are provided. The stage debugging results indicates the functions of the hardware circuit and FPGA logical design run well. This examination circuit board will become an effective tool to the functional testing and research on the ONTs.