Jitter Essentials

A practical course for understanding and working with jitter

taught by Gary Giust, PhD   Biography

Next Class

None currently scheduled. Contact JitterLabs for more information.


The public's insatiable demand for data requires faster data-communication rates, where timing uncertainty (i.e. jitter) occupies a larger portion of a system's overall timing budget. To advance system performance, each new generation of technology must conquer the effects of jitter.

This is a fundamentals course on jitter in clock and data signals, covering a wide survey of topics. Participants will learn the definitions of various types of jitter (including phase noise), understand which type of jitter is important to their application and why, plus learn how to propagate jitter through a system, create jitter budgets, measure and minimize jitter, and more. Emphasis will be placed on developing a working knowledge of jitter, such as establishing a common language, understanding jitter beyond the definitions, visualizing relationships between different types of jitter, and understanding jitter requirements to comply with high-speed serial-data standards.

Jitter Essentials is designed for anyone regularly exposed to jitter wanting a deeper appreciation of the subject. All necessary concepts are developed from first principles to build a foundation for clearly understanding a broad survey of jitter topics, with an emphasis on jitter in (1) clock signals and (2) high-speed serial data signals. The theories presented are punctuated with practical applications and useful insights. Key course principles are reinforced with quizzes, whose answers are reviewed in class.

Course Goals

The goal is to impart a practical working knowledge of jitter. You will walk away with a clear understanding of


Two days on-site, or live online class.

Course Outline

Part 1: Understanding Jitter

What Is Jitter?

Jitter as a branch of signal integrity. Timing and amplitude noise. Jitter, wander, and skew. AC versus DC timing noise. Timing events.

Sources of Jitter

Shot, thermal, and flicker noise. Reflections. Crosstalk. EMI. AM to PM conversion.

Defining Jitter

Time-interval error, period jitter, half-period jitter, cycle-to-cycle jitter, N-cycle jitter, N-cycle to cycle jitter, half-period cycle-to-cycle jitter, phase noise, phase jitter, short-term jitter, long-term jitter, edge-to-reference jitter, edge-to-edge jitter. A framework is constructed to organize jitter in a clear manner.

Matching Jitter to Your Application

Which jitter does your application care about and why? Clocks driving synchronous logic, DDR synchronous logic, pixelated systems, downstream PLLs, PLLs for on-chip deskewing, serial-bus TX PLLs, serial-bus RX PLLs, data converters. Parallel versus serial buses. PLLs used for achieving zero-delay. Oscillators. Spread-spectrum modulation.

Tools for Viewing Jitter

Understanding and working with histograms, eye diagrams, phase-noise plots, and each of their associated units for reporting jitter.

Components of Jitter

Random versus deterministic jitter. Gaussian distributions. PDFs, CDFs, histograms, RMS, and standard deviation. Data-dependent jitter, periodic jitter, duty-cycle dependent jitter, bounded uncorrelated jitter. Total jitter. Ways to organize jitter terminology to keep everything clear.

Jitter Relationships

Visualizing the relationship between TIE, phase jitter, period jitter, and cycle-to-cycle jitter.

Part 2: Working with Jitter

Analyzing Jitter in High-speed Serial-data Links

PLLs and jitter. Anatomy of a serial-bus link. Jitter generation, jitter transfer, jitter tolerance, bit-error rate, PRBS, clock/data recovery, jitter filters. Common test set ups, and measurement points. Calculating BER from Gaussian statistics. Converting RJ RMS to peak-peak at a given BER. Deriving a BER bathtub curve. Q-scale. The PAM4 (r)evolution.

Phase-Noise Conversion

Converting phase noise (dBc/Hz) into phase jitter (ps RMS). Free conversion tools. How to address spurs. Analyzing SERDES reference clocks.

Jitter Budgeting

Review of jitter mathematics. Creating a practical jitter budget. Example physical-layer budget. Assumptions. Breaking assumptions.

Jitter Decomposition

The dual-Dirac model. Limitations of dual-Dirac. Tail fitting, BER bathtub, and spectral methods for decomposition. Common tests for complying with industry standards.

Jitter Equipment and Measuring Jitter

Comparisons, tradeoffs, and recommendations for real-time and equivalent-time oscilloscopes, bit-error ratio testers, spectrum analyzers, phase-noise analyzers. Using confidence intervals to determine how long to measure BER in high-speed serial links.

Who Should Attend?

Anyone exposed to jitter on a regular basis may benefit from this course.

Representative participant companies include:


“Great crash course in understanding jitter and its impact in SERDES communication.”

Senior Test Engineer, American Honda Motor Company

“This class is really helpful to understand jitter basics. The instructor is very knowledgeable in this topic. My recommendation if you are taking this class is to ask as many questions as possible. Also, try brushing up on some college level statistics.”


“A must attend course for all those working on high speed serial links. I will make it a yearly requirement for me until I retire.”

SI/PI Engineering Director, Accton Technology

“We make decisions every day based on what we measure. Depending on how well we understand those measurements and how they apply to our goals, we can make poor choices. If you need to understand Jitter and how it impacts your application, this is a class I would highly recommend. This helps you understand the fundamentals and gives you the tools to make informed decisions in the real world. Gary's teaching style combined with industry experience makes this course a must have in my book!”

Manager, Solutions Architecture, Mentor Graphics

“I think every engineer in wireline transceiver design field must take this class.”

Senior SERDES Design Engineer, Apple

“This is one of the best courses I've attended in recent memory. The instruction was highly engaging and articulate and fostered a productive and efficient learning environment. Theory and concepts were presented with context and in reference to applications such that the material was very consumable. All discussion was comprehensive and illuminating, either reinforcing or introducing phenomena and relationships. The class structure encouraged analysis and ensured that attendees with all levels of familiarity were sure to benefit, either via a fresh perspective or a deeper understanding of the material and relationships therein.”

Hardware Validation Engineer, Amazon Lab126

“Gary's jitter course hits the top of my list of all time best knowledge sources on jitter. It is packed with information relevant to modern high speed systems and it is very well presented. The quizzes made me remember what I learned. The material is extensive beyond what I thought would encompass. I had read Mike Li's book on Jitter and I thought that covered most of it, but not really. You have a lot more material here. The strength is not just the in-depth knowledge, but also the good ability to explain it in simple terms, and the dedication and commitment to put together these courses. Big applause for you. Thank you! ”

SI/PI Engineering Director, Accton Technology

“This is an excellent course to take for understanding jitter, which is always an elusive subject in the industry. It's the best course at UCSC-extension I've taken.”

Sr. Staff Design Engineer, Qualcomm

“This course is a must-have for anyone working in the area of high-speed data links.”

R&D Director, Insigatech

“Excellent course. A perfect introduction for someone looking for a career in validation. Gary is patient and helpful in making you understand the topic.”

Hardware Validation Engineer, Oracle

“Every EE should have a background in this topic.”

Design Engineer

“Great introductory course that opens the way for further independent thinking and analysis of jitter.”

Signal Integrity Engineer, Cisco Systems

“I really liked the way the instructor started with showing datasheets and how different manufacturers present confusing data. The rest of the course proceeded to demystify the different types of jitter sources and jitter measurements. The level of mathematics was just right for practicing engineers to be able to do calculations in the lab. A very well taught and useful course.”

Engineering Manager, Broadcom Corporation

“This course offers an in-depth and technical treatment of jitter essentials that is strongly suited to practicing engineers.”

Hardware Engineer, Ditech Networks

“The class began with a great introduction of definitions and principles, making the rest of the class easier to follow.”

Hardware Engineer

“Great class with very thoughtful exercises.”

Signal Integrity Engineer, Cisco Systems

“An excellent crash course in jitter, for students looking to brush up on knowledge and skills.”

ASIC Signal Integrity Engineer, Cisco Systems

“Great Class!”

Program Manager, Verigy

“Jitter is an elusive subject, hard to grasp through textbooks. This course reveals all about jitter, in an intuitive way, that is essential for solving everyday problems more efficiently and effectively.”

Senior Design Engineer, Kawasaki Microelectronics America

“Great class for all engineers at all levels!”

Component Engineer

“Filled with practical stuff not found in textbooks.”

System Engineer

“This course provides very practical insight and information on the subject of jitter. It has excellent coverage of the topic from fundamentals to industry-level analysis and techniques. The course is structured in a very clear and organized format.”

Senior Characterization Engineer, Xilinx