Signal Integrity Design Of OSDR5000 High-Speed Data Processing System

Nowadays the electronic system is swift developing to the high speed and miniaturized direction. It becomes suspends in front of a designer's important topic--how to raise system's speed during reduction electron system volume's.In the high speed PCB design, the scale of system is getting bigger and bigger, the I/O number are getting more and more, the PCB interconnection density enlarges unceasingly, the clock rate is getting higher and higher, the signal peripheral speed is getting quicker and quicker, cause high-speed circuit's reflection,the crosstalk,the transmission delay,the ground/the electricity plane noise equi Signal Integrity question becomes more and more prominent. But discovers and analyzes these questions on existing PCB is a very difficult matter, even if found the question PCB which completed to implement the effective solution also regarding one to spend the massive time and the expense. If comparatively, in the design initial period and in the design process considered that these aspects the influence, it spends fewer time and expenses in reviseing the similar question, even can avoid having such question. Therefore we urgent needs to seek for one method, enables search,discover and eliminate or reduce the influence of these questions in the circuit design process.Using the Signal Integrity simulation method and the correlation technique, may carrie on the signal rule analysis in the earlier period of the PCB design (for example the sequence and essential signal analysis), then put the electrical rule that obtained from analyzing in routing tools to carry on the concrete routing design, like this then guarantees the signal quality in the design process, may also liberate the manpower, raise the rated capacity, satisfy the market requirement, but this is also precisely the nowadays international leading PCB design method and the flow,it is unable to achieve this that is separated from the Signal Integrity simulation analysis. It was already became product design the successful committed step that integrates the Signal Integrity simulation analysis to the product development, particularly the high speed PCB design, provides optimized finally for the product design the solution.The Cadence Corporation in view of PCB Design Studio issued one tool whith is a function very practical for high-speed circuit design and the Signal Integrity analysis -Allegro PCB SI, it carries on the simulation design and the analysis tool in the Cadence software, it has provided the strong simulation function, and it is very concise of the modelling way , very convenient of the utilization. According to using this simulation software folds the layer stacks sorting, the PCB coefficient of dielectrical loss,medium thickness, the position which as well as the line width the signal plane institute and so on judges some PCB line whether to belong to the microstrip line, belt-shaped line, wide band coupling belt-shaped line, and acts according to the different formula automatic computation holding wire's impedance as well as the signal reflection, the crosstalk, electromagnetic interference and so on, thus may carry on the restraint to the wiring to guarantee the signal integrity of PCB.This article introduced some basic concepts of the electromagnetic compatibility, the signal integrity as well as Cadence software, and unify the actual design experience, elaborated in OSDR5000 processing system of High-speed data circuit typical signal integrity question, through the actual circuit design as well as unifies the Cadence Allegro PCB SI software simulation experiment, has analyzed and processed including the reflection, overshoot, ringing,monotonous and other Signal integrity questions, completed the design of high speed digital circuitry, enabled the product to be possible a more reliable application, saved the manpower and resources, saved the cost, sped up the product going on the market time, brought the good benefit to our company.