246 



BELL SYSTEM TECHNICAL JOURNAL 



35 



30 



§^^5 



20 



°^ 15 



o 

 ti^lO 



500 



3000 



Fig. 



1000 1500 2000 2500 



FREQUENCY- CYCLES PER SECOND 



7 — Effective resistance-frequenc}- characteristics toll cable loading coils 



Fig. 8— Residual magnetization characteristics of compressed powdered iron core 

 and iron wire core loading coils 



