Investigation of Shielding Effectiveness and Differential Alien Crosstalk Correlation in Twisted Pair Cables

摘要

Power sum near-end alien crosstalk in BASE-T cabling is difficult to measure but is an important transmission impairment to characterize for 10G and higher signaling rates. The laboratory measurement process involves the construction of bundles of cables and multiple connections to a test set before the parameter can be fully characterized. This complexity has prompted standards organizations to explore the correlation between alien crosstalk and more easily characterized parameters such as TCL or coupling attenuation. This paper reviews the conclusions of past investigations along with data collected on six prototype cables to support the conclusion that TCL is an unreliable method of establishing PSANEXT performance. The data also shows that coupling attenuation and PSANEXT are correlated. The data is used to establish a continuous function relating coupling attenuation and PSANEXT. This function may be useful as a guideline but the quality of the fit shows that the coupling attenuation/PSANEXT relationship is not deterministic.