Jitter, Noise, and Signal Integrity at High-Speed: A Tutorial--Part IV

Historical Overview of Jitter, Noise, BER, and Signal Integrity

During the last two decades, two books were published with significant space dedicated to jitter analysis.^{16, 17} During that time, most communication architectures operated at a data rate of less than 1 Gb/s. Jitter was not as serious then as it is today, when most leading communication links are running at rates of 1 to 10 Gb/s.

The book by Trischitta & Varma¹⁶ in 1989 was mostly focused on the accumulated jitter in a network system and jitter related to some specific components in an optical network at the time, including regenerators, retimers, and multiplexers. The jitter handling in this book was tightly coupled with the link architecture of almost 20 years ago, so many of the concepts and theories in this book do not apply well to the serial link architectures developed after the 1990s.

The book by Takasaki¹⁷ in 1991 treated digital transmission design and jitter in the same context. This book is weighted more toward digital transmission, with only two chapters dedicated to jitter topics, covering jitter generation and accumulation. This book does discuss jitter classification in some way. The major point of Takasaki on jitter classification is that there are two types of jitter: random and systematic. However, it has no quantitative math model discussion on the jitter classification scheme. It also has no further discussion of the jitter component beyond random and systematic. The discussion of jitter accumulation is largely based on the repeater component in a network.

In the past 15 years, significant progress has been made in the field of understanding jitter, and related new theory, definition, analysis methods, and measurement tools. In particular, more rigorous definition of and theory about jitter and its associated jitter components have been developed (such as ^{15, 18}, and ¹⁹, to name a few). Now jitter and noise component concepts have been widely accepted and adopted by many serial data communication standards. In fact, jitter and noise component concepts are required for determining the link jitter budget, for debugging and diagnostics for designing and testing most of the multiple Gb/s serial data links, and for setting standards. In addition, a generic jitter transfer function for a linear or quasi-linear system has recently been developed. Such a method can be applied to jitter analysis for most of the serial data communication links and standards ^{15, 20}. The combination of the statistical and system transfer function elements of a link system in estimating overall jitter, noise, BER (JNB), and signal integrity (SI) performance has put the research and application in those areas on a new historical plateau.

In light of that significant progress in JNB and SI, as well as the ever-increasing importance of their roles in > 1 Gb/s serial communication links in both network and PC applications, a new book summarizing that progress--with an emphasis on the latest definitions, theories, and applications, as well as simulation modeling, measurement, and analysis technologies--is apparently greatly needed.

Overview of this Book
This book systematically presents the latest developments and advancements in jitter, noise, and BER (JNB) and SI. It guides you from the basic math, statistics, circuit, and system models to the final practical applications. It covers fundamental theory, to JNB and SI simulation/modeling, to JNB and SI diagnostics/debug and compliance testing, with an emphasis on two major applications: clock and serial data communications. It tries to keep a good balance and coupling between theory and practical applications.

As you have seen, this chapter is a high-level overview of JNB and SI basics. This chapter introduced the JNB component classification scheme, JNB interrelationship, root-cause mechanisms, JNB measurement references, clock recovery, and associated JNB transfer functions.

Chapter 2 reviews and introduces the basic theories on statistics, linear time-invariant (LTI) systems, and digital signal processing that you need to quantitatively understand and model JNB and its related components. Also introduced in this chapter is the statistical signal process theory that is used to quantify the JNB spectrum and power spectrum density (PSD).

Chapter 3 describes the jitter component in a quantitative manner. Detailed root causes and mathematical models and treatments for each jitter component are given. This chapter lays the necessary physical and mathematical foundation for jitter and noise to warrant the precision of the estimations. Jitter component math models can be applied to noise components similarly.