AN IMPROVED THREE-CHANNEL CARRIER TELEPHONE SYSTEM 69 



designed to have unequal ratios,f"minimizing the loss to through 

 transmission at the expense of greater loss in the feedback circuit. 

 Including the transformers in the feedback path makes them also 

 beneficiaries of the feedback with a resultant reduction in impedance 

 irregularities, transmission distortion and modulation products. 



90 



80 



70 



2 50 



< 



40 



30 



10 



15 20 

 FREQUENCY -KC 



25 



30 



35 



Fig. 15 — Gain frequency characteristic of amplifier. 



The amplifier has a gain of 50 db with provision for increasing it to 

 52 db when used as a terminal transmitting amplifier. Gain-frequency 

 characteristics are shown in Fig. 15 for the 50-db gain condition with 

 and without the feedback connection. The effect of feedback on 

 transmission distortion is evident in this figure. 



