| Electromagnetic-compatibility (EMC) problems, including electromagnetic interference (EMI) and signal integrity (SI), have escalated in recent years, as a result of increasing clock-speeds and faster edge rates in current digital technologies. Noise problems are complicated by parasitics that are not completely understood. A radiated-noise problem can generally be broken into separate parts. The radiating antenna and the noise-source mechanism resulting from parasitics are studied herein. A method for categorizing noise sources, or the conversion of differential-mode energy to common-mode energy, is proposed and supported with numerical and experimental results.; EMC engineers are interested in quantifying the parasitics associated with noise-source mechanisms. Tools that can analyze the parasitics may be used to shorten the design cycle and increase productivity. Equations are developed for predicting the magnitude of the noise source on reference planes in microstrip-circuit geometries. The equations are supported by experiments.; Stacked-card and modules-on-backplane configurations are used in high-speed digital designs to conserve real-estate. The stacked-card configuration is studied for possible contributions to electromagnetic interference (EMI). An experimental and numerical investigation is presented to provide designers some direction for reducing EMI. The antennas inherent in the design are evaluated, and the noise-source mechanism at the bus connector is analyzed.; A method for decomposing loop inductance is proposed for use in calculating parasitics that lead to EMI. The decomposed inductances, called branch inductances, may be used to model the magnetic flux that wraps a particular conductor, and ultimately couples an EMI antenna. The branch-inductance method is contrasted with the partial inductance method analytically and experimentally for use in predicting radiated EMI. |
