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BELL SYSTEM TECHNICAL JOURNAL 



As an example, suppose it is desired to calculate the approximate 

 number of {2A + B)-type products falling in channel number k when 

 the number of channels is large. If Xi > xi, this type of product may 

 be either of form 2xx + x^ or Ix^ + Xi. Both are included by the 

 expression 



V2A+B 



ri 



giz{2xi-\-Xi\ _|_ gtz (11+2*1) 



— J I g2in2z gi(2ni+n2)z gt(ni+2n2)z _|_ aZinj 



dxi 



dz 



^ 0, k < 3wi 



|(^ - 3wi), 



K3w2 - k), 

 , 0, ^ > 3w2. 



Sfii < k < 2ni + W2 

 Wi + 2«2 < k < Sfti 



(11) 



The method may be generalized to include the calculation of the 

 modulation spectra produced by fundamentals having specified arbi- 

 trary spectra by inserting the appropriate function of the power in unit 

 band width at Xi, Xi, • • • Xn in the integrand of (6). 



