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BELL SYSTEM TECHNICAL JOURNAL 



of simultaneously active channels will be greater than the average 

 number Nt of active channels. Since the multi-channel peak factor 

 decreases as n increases, the peak factors for n = Nt active channels 

 may be safely used. A more detailed analysis, feasible only for very 

 small systems but avoiding the use of this approximation, shows that 

 its effect is small and tends to give load capacities slightly higher 

 than actually required, but the difference diminishes rapidly as the 

 size of the system is increased. 



For the uncontrolled volume condition, therefore, the multi-channel 

 peak factors are read from Fig. 5 for values of « = Nt. They are 

 added to the equivalent volumes obtained from curve B of Fig. 6, and 



0.9 



Q 

 LlJ 



Q 0.8 



UJ 

 UJ 

 O 



X 0.7 



LJ 

 (0 



ui 0-6 



3 0.5 



O 



> 



>- 0.4 



g 0.2 

 0.1 



-22 -20 



-18 



-16 -14 -12 -10 -8 -6 -4-2 2 

 EQUIVALENT VOLUME IN DECIBELS 



Fig. 9 — Equivalent volume distributions for systems of N channels. 



reduced to single frequency power as previously described for the 

 volume controlled case. Curve B of Fig. 7 is obtained in this manner 

 and shows the load capacity required in an amplifier for an iV-channel 

 system in which the volumes of each channel are distributed in accord- 

 ance with curve A of Fig. 1. The load capacity which is approached 

 asymptotically as N increases indefinitely is represented by curve D 

 of Fig. 7. 



The load capacities given by Fig. 7 are valid only for systems for 

 which the basic single-channel data apply. As these may not hold in 

 specific cases, and may be subject to modification in the future, 

 estimates of the effects of small changes in these data are useful. 

 These effects cannot be described simply for moderate numbers of 



