DESIGN FACTORS OF THE 1553 TRIODE 523 



If only the output circuit is involved, then N = n^ and the band of the 

 amplifier, being shaped differently, is given by a different relation: 



BAA) = ^ VW^^l. (Al-12) 



In other words, a band shaped by only one circuit has the shape of (12), 

 while a band shaped by two circuits has the shape (11). The maximum 

 voltage gain is 



2 I F21 I 



I To I = I r(coo) I = ^/ r r (^ -l \(\ j. ^ (Al-13) 



Substituting for the G's in terms of the bandwidth, we have for the 

 equal-(2 case (from 11) 



I r. i = ^-^ , ^^^^^ 1 (Ai-14) 



27rVCieC2. V(l + Mi)(l + M2) ^^ 

 and for the unequal-Q case (from 12) 



These equations give the relationship between the gain and bandwidth 

 of a transmission system shaped by two or one independent circuits, 

 respectively. The comparison between these two cases is not quite straight- 

 forward. First, the band shapes (11) and (12) are different, although this 

 difference is small enough to be ignored for iV < 2 (6 db down). Second, 

 the gain varies differently as the band is widened; the equal-Q case loses 

 gain at 6 db per octave in bandwidth, the unequal-(2 case only 3 db 

 per octave. The comparison therefore depends on the bandwidth chosen. 

 However, these formulas are still quite useful, especially in comparing 

 two amplifiers of the same type or in optimizing an amplifier of one of 

 the types. 



From the equal-<2 formula one notices that the product of insertion 

 voltage vain and bandwidth does not depend on the bandwidth, but is a 

 figure of merit by which two amplifiers of the same type (i.e. equal Q) 

 but different gains and bandwidths can be compared. Since 



Cu = Cii + Cp\ ; Cie = C22 + Cp2 



•--(w;„J(^,^c,Y,^£ 



( 



2\/iV 



V(l + Mi)(l + M2)> 



(Al-16) 



