Crosstalk in Balanced, Twisted Pair Circuits

An investigation of the prediction of crosstalk to balanced, twisted pair circuits is presented. Experi­ mental results are given which show that the differen­ tial mode induced voltage can be extremely sensitive to the wire twist and in practical situations is not predictable with any reasonable degree of consistency. The common mode induced voltage appears to be rela­ tively insensitive to the wire twist. The prediction of crosstalk to balanced twisted pairs which utilize differential line drivers and line receivers is inves­ tigated. It is shown that the common mode induced voltage can be predicted by replacing the twisted pair with a single wire above ground having appropriate loads. Experimental results are given to support these findings.