Chaitanya Sreerama

Effects of skew on EMI for HDMI connectors and cables

This paper describes the effects of intra-pair skew on electromagnetic interference (EMI) for High Definition Multimedia Interface (HDMI) connectors and cables by analyzing both simulations and measurement results. Measurement methods like VLSI GTEM and current clamps are used to show the effects of skew on EMI for terminated HDMI connector/cable assemblies. Numerical simulations are used to study several factors contributing to skew in a differential cable and their impacts on EMI. Both the measurement and simulation data show a clear trend of increased EMI that corresponds to an increase in skew. The data indicates the need for a lower cable skew specification for high speed connectors and cables to better facilitate compliance with FCC regulations

Performance bounds of MIMO receivers in the presence of radio frequency interference

Multi-input multi-output (MIMO) receivers have generally been designed and their communication performance analyzed under the assumption of additive Gaussian noise. Wireless transceivers, however, may also be affected by radio frequency interference (RFI) that is well modeled using non-Gaussian impulsive statistics. In this paper, we derive bounds on the communication performance for a two transmit, two receive antenna MIMO system in the presence of RFI. Our contributions include derivation of (1) channel capacity in the presence of RFI, (2) probability of symbol error for uncoded transmissions, and (3) Chernoff bound on the pairwise error probability and cutoff rate as a measure of the throughput performance for coded transmissions. Comparison with the communication performance bounds for receivers designed assuming additive Gaussian noise demonstrates degradation in communication performance in the presence of RFI.

Flexible printed circuit meshed ground plane modeling methodology

Flexible Printed Circuits (FPCs) are widely used inside electronic devices because they are easy to customize, enable relatively dense interconnect routing, and are the most physically flexible. Physical flexibility can be further enhanced by using a meshed ground/reference plane. Unfortunately, meshed ground planes can induce significant signal integrity problems that can roadblock high-speed channel design if not properly modeled. This introduces unique modeling challenges that commercially available software are ill equipped to solve. This paper presents a new simulation methodology to model FPC meshed ground planes in high-performance compute systems using existing quasi-TEM solvers with excellent measurement correlation.