288 



BELL SYSTEM TECHNICAL JOURNAL 



Example 3b — 19-Gauge Quadded Nox-Loaded Toll Cable 



Two complete RC functions plus a resistance are required to give a good 

 simulation for non-loaded toll cable when the simulation is carried through 

 the voice and carrier frequency ranges. The impedance function for 19 ga. 



200 



1000 



400 600 800 



RESISTANCE 



Fig. 4 — Graphical design of two-terminal balancing network for 22-ga. non-loaded 

 exchange area cable. 



Table Ill-a 

 22 Gauge N on-Qiiadded Non-Loaded BSA Exchange Area Cable 



Freq. 

 kc 



0.2 

 0.5 

 1.0 

 2.0 

 3.0 



Line Impedance 



Rect. 



915— j905 



580— j565 

 415— j400 

 295— j280 

 250— j220 



Polar 



1287/44.7 

 808/44.2 

 576/44.0 

 407/43.5 

 333/41.3 



Network Impedance 



Rect 



1380— j725 

 705— j 725 

 390— j460 

 285— j245 

 260— j 165 



Polar 



1555/27.8 



1010/45.8 



6O3/49.7 



376/40.7 



308/32.4 



Computed 



Return 



Loss— 



db 



15.0 

 19.1 

 25.2 

 26.6 

 21.2 



toll cable is plotted on Fig. 5. The method followed in determining the 

 elements is somewhat as follows: Ri will be given by the intercept of the 

 function on the R axis and is 130 ohms. Next look at the low-frequency range 

 determined by R£z and draw a semicircle which approximates the given 

 function in the range of 200-500 cycles. The diameter of this semicircle 



