668 THE BELL SYSTEM TECHNICAL JOURNAL, MAY 1954 



Fig. 5 — Discrimination versus 0/iv for the cosine coupling disbribution. 



poorer discrimination at values of Q/-K slightly above the first peak. In a 

 similar way Fig. 6 shows better discrimination than Fig. 5. 



Linear superposition of forward or backward currents may be em- 

 ployed to advantage when designing a coupling distribution. The second 

 line of Fig. 4 gives the discrimination for a coupling function composed of 

 a raised cosine plus uniform coupling. For a value of c = 22.4 and A; = 1, 



50 



45 

 CO 40 



LU 



eg 



a 35 

 Q 



Z 30 



z 



^25 

 < 



Z 

 220 



a. 

 u 

 ^ 15 



Q 



10 



5 







1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 



e 



Fig. 6 — Distribution versus d/ir for the raised cosine coupling distribution. 



