Halvor Liland and Bjørn Sveum, Liland Technology and Rohde & Schwarz:
Analysis and Verification of Signal Reflections in high-speed Connections
As data rates in serial links climb towards 10 GT/s and beyond, the margin for error in the physical layer vanishes. At these frequencies, interconnects can no longer be treated as simple wires, and minor impedance discontinuities can have catastrophic effects on signal integrity. Among the primary adversaries of a clean signal is the phenomenon of reflection - energy bouncing back from impedance mismatches caused by vias, connectors, and package transitions.
This presentation provides some theory of the mechanics and mitigation of signal reflections in high-speed digital design. Following the theory, it will examine a simulation workflow. Finally, it will bridge the gap between simulation models and physical reality by presenting real-world measurements from a prototype unit using a Vector Network Analyzer. It will correlate the simulated expectations with the measured reality.