8 BELL SYSTEM TECHNICAL JOURNAL 



present in the modulation of each station the radio frequency waves 

 will be of the form E{\ + J/j cos pit + -1/2 cos p2t -{- • • • ) cos wi/ and 

 e(l + 7ni cos qit + m^ cos qit + • • •) cos uoi- For every frequency of 

 the former case which contained .1/ as a factor of its amplitude we shall 

 now have several frequencies respectively proportional to Mi, Mo etc. 

 while an analogous new group will correspond to the former frequencies 



.01 



.001 



.0001 



.001 



.01 



T=RATIO OF CARRIER AMPLITUDES 



Fig. 1 — Relative am])litiides of undesired frequencies as a function of the ratio of 

 the amplitudes of the desired and the interfering carriers. .Modulation of both 

 stations small and equal. 



containing m. Hence we shall have two frequency spectra derived 

 from the desired speech spectrum containing the ^'s, but one of the 

 spectra will be shifted upward in frequency by an amount ujlir and 

 the other downward by the same amount. Two additional spectra 

 will be derixed in a similar manner from the undesired speech spectrum 

 containing the (/'s. The frequencies of the type {p ± q ± u)'lTr\\\\\he. 



