Study On Some Issues Of Jitter In High-Speed Serial Communication

High-speed serial communication has become the mainstream of high-speed interconnect technology, and jitter analysis is an important method to assess the performance of high-speed serial communication system.In order to evaluate the performance of the high-speed serial link as well as the bit error rate, it is necessary for us to have a complete theoretical model of jitter in high-speed serial link. Line codes are often used for high-speed serial data transport, such as 4B/5B, 8B/10B, 64B/66B etc. Multi-level signalings such as PAM-4 and PAM-8 are also adapted in high-speed serial communication. However, most of nowadays evaluation of different line codes and different multi-level signaling are based on qualitative analysis, or comparative analysis of test result, which are lack of uniform persuasive assessment.In this dissertation, by analyzing the sources of jitter, we established a theoretical model of jitter starting from the basic concept of jitter theory and the high-speed serial link model. The accuracy of this model is verified by applying it to many real working situations. Another aim of this dissertation is to find out different applications for this jitter model. It is applied to analyze the impact of different line codes on jitter and investigate the jitter in multi-level signaling.The structure of this dissertation is as follows:The first is about the introduction and background; it introduces the research methods and purpose of this dissertation.The second chapter describes the definition of jitter, common methods for jitter analysis, jitter classification, source and mathematical model of each jitter component, and finally gives out the mathematical model of the relationship between jitter and bit error rate.Chapter 3 is devoted to the mathematical description of different jitter components based on the model of high-speed serial communication. The influence of channel on jitter components of different sources are discussed here. We will introduce the method for decomposition and calculation of DCD and DDJ. The influence of RJ and PJ from the clock path and additive noise in the channel on jitter at the receiving end is also discussed in this part.In chapter 4, based on the model proposed in chapter 3, a complete algorithm for total jitter distribution and bit error rate calculation from the S parameters of channel is proposed. The possible impact of test equipment, test methods and jitter analysis methods adopted in the jitter analyzer on test result is discussed. The bandwidth limitation of the pattern generator will greatly exacerbate the jitter in the test, and a correction method is proposed. Finally, a series of experiments of jitter test are carried out and the test result is compared to the estimated result to verify the accuracy of the model.In chapter 5, we first introduce some common line codes, such as 4B/5B, 8B/10B, 64B/66B, PRBS, and then analyze the effect of different line codes on jitter in high-speed serial communication system from the perspective of the probability of DDJ. We also estimate the DDJ in first-order low-pass channel and actual channels with different line codes, the result shows that 4B/5B and 8B/10B have similar effect on jitter. The coding efficiency of 4B/5B and 8B/10B is only 80%, as data rate increases, the rate penalty gets worse, and high efficiency line code such as 64B/66B will be a better choice.In Chapter 6, we first give the definition of“ideal reference time”and jitter in multi-level signaling, and then we apply the jitter analysis method used in NRZ signaling to analyze jitter in multi-level signaling. Take PAM-4 signaling as an example, the jitter in PAM-4 signaling though a first-order low-pass channel and actual channels is analyzed. Comparing to PAM-4 signaling, according to the horizontal and vertical eye opening of the eye diagram, NRZ signaling may have better potential for high-speed serial data transmission.Chapter 7 summarizes the main ideas and the innovations in this dissertation, and points out the direction of future work.