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BELL SYSTEM TECHNICAL JOURNAL 



increases indefinitely. Therefore, it does not come within restriction 

 (BI) and consequently the reasoning leading up to the rule does not 

 apply. 



The admittance in question can be made up by bridging a capacity 

 in series with a resistance across a resistance line. This admittance 



W- PLANE 

 Fig. 8 — Illustrating Example 8, without distributed constants. 



obviously does not approach zero as the frequency increases. In any 

 actual network there would, however, be a small amount of distributed 

 capacity which, as the frequency is increased indefinitely, would cause 

 the transmission through the network to approach zero. This is 

 shown graphically in Fig. 9. The effect of the distributed capacity is 



W-PLANE 

 Fig. 9 — Illustrating Example 8, with distributed constants. 



essentially to cut a corridor from the circle in Fig. 8 to the origin, which 

 insures that the point lies inside the locus. 



Appendix I 

 Alternative Procedure 

 In some cases AJ{iiS) may be given as an analytic expression in 

 (ioj). In that case the analytic expression may be used to define w for 

 all values of z for which it exists. If the value for ylJ(ico) satisfies all 

 the restrictions the value thus defined equals the w defined above for 

 — :x; < CO only. For — oo < .v < it equals the analytic continu- 

 ation of the function w defined above. If there are no essential 



