THE TORONTO-BARRIE TOLL CABLE 



603 



resistance from that of the main cable. (The geographical spacing 

 on the quadded 0.062 mf. cable was 4100 feet as compared to 3000 feet 

 on the non-quadded cable.) 



Since representative return loss data had already been obtained for 

 circuits under working conditions (Fig. 8), the completion return loss 

 measurements were made for the network building-out capacity condi- 

 tions assumed for the theoretical return loss characteristic (curve 'A,^ 

 Fig. 8). The results thus obtained are shown in Fig. 12 for Barrie 

 and Fig. 13 for Toronto. In Fig. 12, the theoretical curve is shown for 



25 



UjO 



1200 1600 2000 2400 



FREQUENCY IN CYCLES PER SECOND 



2800 



3200 



Fig. 12 — Return loss — frequency characteristics. Measured from Barrie to 

 Toronto on 53 pairs; building-out condenser adjusted to theoretical value; curve 'A ' 

 is the 63 per cent return loss computed from attenuation and irregularity function 

 measured on cable. 



comparison, and it is to be noted that the agreement with actual results 

 is remarkably good. The results obtained at Toronto are better than 

 those at Barrie, except below 600 cycles, which is the frequency range 

 of the impedance departures discussed in connection with Figs. 9, 10, 

 and 11. 



Analysis of the near-end crosstalk measurements indicated that at 

 Barrie 98.8 per cent, and at Toronto 96.3 per cent of the combinations 

 were equal to or better than the 74.5 db assumed for the preliminary 



