Keywords and Phrases
Cable harness; Glass weave; PCB; Radiated immunity; Skew; S parameters
"We develop an efficient method to model RF immunity of multiwire cable harnesses and study differential P/N skew effects on channels, channel performance and specifically on the eye diagrams at the SerDes receiver.
External radiation can induce unwanted signals in transmission lines. For example, external radiation from an antenna induces common-mode currents on the outer surface of cable shields. This common-mode signal makes its way through the shied due to its imperfections, inducing the inner common mode. When twisted pairs inside the cable are not balanced, inner common mode is in turn converted to the differential mode, which might compromise performance of sensitive electronics connected to the cable harness. In paper I, we develop the equivalent circuit model and the methodology for prediction of the worst-case envelope for differential mode signals induced in cable harnesses placed over a ground plane. The cable harness consists of twisted wires which are slightly unbalanced within the harness connector region. The induced signals are calculated using the transmission line theory avoiding the need for any 3D calculations. The results are validated by experimental measurements.
Differential P/N skew is one of the main performance-limiting issue for high-speed SerDes links. The P/N skew is arrival time difference between two single-ended signals in a differential pair. It is commonly caused by unmatched delays of P/N lines of a differential pair but even for perfectly matched physical length cases, P/N skew can be caused by any other asymmetry between P/N lines. In the printed circuit board, relative location of fiber bundles with respect to conductors is random and results in uncontrolled P/N skew. In papers II, III, we derive analytical equations for S-parameters as a function of the P/N skew and frequency for weakly and strong coupled transmission lines. We also study the P/N skew effect on SerDes performance by measurements"--Abstract, page v.
Electrical and Computer Engineering
M.S. in Electrical Engineering
National Science Foundation (U.S.)
Missouri University of Science and Technology
Journal article titles appearing in thesis/dissertation
- Prediction of worst-case radiation immunity in cable harnesses
- Effective channel budget technique for high-speed channels due to P/N skew
- Effect of time delay skew on differential insertion loss in weak and strong coupled PCB traces
xiii, 56 pages
© 2019 David Nozadze, All rights reserved.
Thesis - Open Access
Electronic OCLC #
Nozadze, David, "Radiation immunity in cable harnesses and differential P/N skew in PCB" (2019). Masters Theses. 7890.