.2.5 Gbps Road Source Development

Data Business has larger proportion than voice business currently, and it has become the main part of telecom business in modern telecom networks already, and packet switching formally becomes the main switch method in the whole networks. Those Qos Problems as, throughput, link utilization, packet delay, delay jitter and packet loss rate in the data communication earned more attentions as well in the recent days. In order to satisfy the requirement of the test, maintenance and management of the packet switching performances, a data packet source (hereinafter called the"Optical Signal Generator") is highly expected. This"Optical Signal Generator"will be acted as simulated customers, and it will do the measurement and evaluation work for all the indexes mentioned above. Besides, this type of data switching source will produce the accordant formulation to the network protocol, and its data frame, sending out time shall also do its best to simulate the real customers in the networks.The traditional method is to use a commercial network data analyzer (PPT) as the data source. However, this type of data source is very expensive, too big in shape, and it cannot produce random data packet which is different in length. It is even harder to implement multiple nodes, multiple sources, and multiple services.The intention of this thesis is to develop a programmable data packet optical signal generator based on the FPGA which composes data generate unit and optical transmitter unit. The thesis finishes the development of the hardware platform and the software program, generates the 2.5Gbps optical serial data packet with the good quality and the length of the data packet satisfy the Poisson distribution. Correctly receiving the data signal with the connection and adjustment of the receiving unit, the searching for the frame synchronization identifier and the establishment of the system frame synchronization as well as getting the target address verify that this Optical Signal Generator is the every random packet data source for use.While solving the problem of high-speed optical source driver, this thesis proposed a new driver circuit– Inductor Coupling Circuit. It has both the advantages of Direct-Coupling Circuit and Capacitor Coupling Circuit. It is also advanced in the following aspects: few components; less infects by the DC base of the on-off circuit; never saturation, and etc.This Optical Signal Generator is simple in structure, cheap in cost, convenient in performance, flexible in application, the Generator not only could meet the requirement...