Research of Characteristics of Transfer Function of Mine-used Twisted Pairs

The transfer function is an important parameter of twisted pairs loop.The paper set two kinds of ADSL test loops with mine-used twisted pairs and studied their transfer functions using transmission line theory.The result showed that the transfer function is influenced by frequency,twisted pair diameter and loop distance.The transfer function of the mixed loop relates to distance of whole loop and subsection,and is independent on order of twisted pair types on subsection loops.