Cable Crosstalk--Effect of Non-Uniform Current Distribution in the Wires

Cable Crosstalk--Effect of Non-Uniform Current Distribution in the Wires By R. N. HUNTER and R. P. BOOTH W h e n wires are close to each other as they are in cable, the m u t u a l inductance coupling between pairs is not a simple n u m b e r , constant at all frequencies. Because of the non-uniform a n d non-symmetrical distribution of current over the cross-sections of the conductors the "effective m u t u a l i n d u c t a n c e " is of the form M = Ma + jMb where b o t h Ma a n d Mb v a r y with frequency. T h i s paper discusses the results of certain measurements which have been m a d e of the effective m u t u a l i n d u c t a n c e between straight wires a n d between cable pairs over a wide range of frequencies extending up to a million cycles. T h i s is of interest in connection w i t h crosstalk problems in cable carrier telephone systems.