A MILLION-CYCLE TELEPHONE SYSTEM 



500 1000 1500 2000 



FREQUENCY IN CYCLES PER SECOND 



2500 



Fig. 9 — Schematic diagram of a coaxial million-cycle system showing frequencies 

 assigned to the different channels. 



This demonstrated that the complete assemblage of parts, including 

 filters which divide the frequency range into the required bands, 

 modulators which produce the necessary frequency transformations, 

 and amplifiers which counteract the line attenuation, introduced very 

 little distortion. Many problems require further consideration, 

 however, before these systems will be ready for design and production 

 for general use. The final systems must have such refinement that 

 they are suitable for transcontinental distances; the tremendous 

 amplifications needed for such distances must have very precisely 

 designed regulation systems, particularly where aerial construction 

 is involved; noise and crosstalk must not accumulate over the long 

 distances; the repeaters must have such stability and reliability that 

 continuity of service will be assured with hundreds of repeaters operat- 

 ing in series and each repeater handling several hundred different 

 communications simultaneously. 



