Exploration of Deterministic Jitter Distributions
While Deterministic Jitter (DJ) is generally agreed to be peak limited, what is less clear is how rapidly its PDF decreases near that limit, especially when the DJ is due to crosstalk.
This paper addresses this and related questions by considering a class of responses which are similar to real system responses but are described by closed form equations. These responses can therefore be evaluated precisely at arbitrary times, allowing the tails of the jitter distribution to be explored in detail. The result is a clearer understanding of when the tails of a DJ PDF can resemble a Gaussian.
How Interconnects Work: Crosstalk Quantification
Crosstalk is unwanted noise from structures coupled to a signal link that degrade the useful signal and may reduce the data transmission rate and even cause complete link failure. All possible signal degradation effects, including the crosstalk, can be expressed with the balance of power.
PAM4 Transmitter Test Challenges
This presentation discusses 400G test and measurement challenges. Specifically, it focuses on performing transmitter measurements of PAM4 modulated signals, discussing some of the pros and cons of using sampling oscilloscopes vs. using real-time oscilloscopes in making PAM4 measurements in the optical and electrical domains.
Advances in VNA-based Signal Integrity Tools and Techniques
As backplane speeds rise, backplane/board/connector design is not getting any easier. In this presentation, we demonstrate new de-embedding techniques integrated into VNA firmware that make frequency-domain signal integrity measurements easier, more accurate, and less error-prone. We also present new tools to predict system response to arbitrary time domain signals. By implementing a “virtual” signal generator for multilevel PAM signals (NRZ, PAM-4, PAM-8, PAM-16), coupled with the impulse response of the measured S-parameters, eye diagrams are produced and updated in real-time.
112 Gbps Electrical Interfaces: Does rate drive architecture or does architecture enable rate?
As the industry plans it’s move to 112 Gbps, a number of signal integrity challenges must be addressed. Technology improvements will no doubt be part of the solution, but it is likely that evolving architectures will also be part of the solution.
This presentation discusses the industry trends driving the need to move forward to 112 Gbps; the electrical channels and electrical architectures anticipated to be part of the 112Gbps components, equipment, and networks; and finally, shares some analysis results based on some of these channels.
Moving Towards 112G PAM-4 Characterization – Challenges, Crux Issues
Al Neves discusses the challenges of attaining good signal integrity beyond 50 GHz. Topics include:
- EDA Tools and Simulation Methodology
- What exactly is “Good SI”
- The “Alamo Strategy” for test fixture architecture
- The “Fabrication Hurdle” – What is it, how to get past it
- A new paradigm for critical SI connector / vendor working relationships
- Why program and project management gets in the way of 70 GHz SI
Electromagnetic Simulation Techniques for High-Speed Connector and PCB Applications
As signal speeds of complex electronics systems increase, component and system designs require more sophisticated, accurate, and user-friendly Electromagnetics based simulation tools. Fast, accurate, EM-based simulation is now an essential tool for any engineering team to achieve product release of high-speed connectors and PCBs. This presentation will discuss advances in Electronics simulation techniques including FEM and Transient Electromagnetic Simulation techniques; Automated Connector/Board Assembly Meshing/Analysis; Electromagnetics Based EMI/EMC Analysis; Crosstalk/Impedance Scanning; Integrated Electronics/Thermal Analysis (Multiphysics); High-Performance Computing; 3D Components, etc.
Methods of Improving 3D EM Model Development and Associated Time/Frequency Domain Measurements
Topics:
- For the Metrologist: Practical calibration methods suited for 3D-EM
- For the Signal Integrity Practitioner: Verification and assurance
- For the 3D-EM Modeler: Time domain processing and 3D-EM model development
Tips:
- Low frequency data is just as important as high frequency in both measurement and models
- Remember the basics: Start with the appropriate calibration and verify it
- Beware of the tools: Understand what they are doing
- Simulate to reduce design turns but measure to close the loop
Robust Method for Addressing 12 Gbps Interoperability for High-Loss and Crosstalk-Aggressed Channels
This presentation addresses a new methodology for 12 Gbps interoperability that combines a concerted family of pathological channels, internal eye monitoring, and external EQ simulation tools, providing insight into an EQ optimization strategy that addresses the specific channel’s mix of crosstalk noise, jitter, and channel loss. This also provides a backplane designer the ability to configure a high-loss, crosstalk aggressed system. The method, combining co-simulation channel optimization, a reconfigurable channel platform, and receiver eye monitoring, has two key benefits; the separation of channel eye opening versus un-equalizable Deterministic Jitter (Dj), and the capability to map loss-crosstalk space for a particular SERDES channel pair, a new concept in SERDES interoperability evaluation. The method is described in detail, followed by relevant case examples using hardware specifically designed for this endeavor. Finally, we compare eye monitor results with the original co-simulation, validating the method.
Measurement-Assisted Electromagnetic Extraction of Interconnect Parameters on Low-Cost FR-4 Boards for 6-20 Gb/sec Applications
Design of interconnects on PCBs for 6-10 Gb/s data rates requires electromagnetic models from DC up to 20 GHz. Manufacturers of low-cost FR-4 PCBs typically provide values for dielectric constant and loss tangent either at one frequency or without specifying frequency value at all, that is not acceptable for the broad-band models. A simple and practical methodology to extract frequency-dependent dielectric parameters on the base of correlation of measurements and simulations is proposed. A board with 30 test structures has been built to validate the extraction methodology and to verify possibilities to predict interconnect parameters with the electromagnetic analysis.
Calibration and De-Embedding Techniques in the Frequency Domain
Topics:
- Calibrate and De-Embedding Concepts
- Selecting a Suitable Measurement Approach
- Examples of SOLT and TRL measurements
- Creating a TRL calibration kit
- Measurements of Calibration Accuracy
- Examples of 3D field solver measure-based correspondence
