NAFI TR-li+Uo 



Referring to equation l6, the performance of the non -optimum 

 conventional system with normalized bandwidth ii can be compared to the 

 Eckart filter system. The relative loss in output SWR of the non-optimum 

 system is conveniently expressed as 



where 6^. is a multiplicative factor depending on § alone, amd given by 



(2f-l) 



s,-.\o-o' ' '" 



(31) 



1 ?- I 



Thus, graphs of SKRo /SMRd (=°) exhibit the same bandwidth dependence as 

 Figure k; the curve corresponding to each value of § is simply moved down by 

 a factor of ^pYgd-Lo); which is a constant for each value of §. The results 

 for equation 30 are shown in Figure 5- I't can be seen that the additional 

 "signal shaping" loss, i.e., the loss in addition to the bandwidth loss 

 shown in Figure h, amounts to some 1 to 2 db, with the higher loss being 

 associated with the shallower relative signal spectral slope, § = 1. 

 Figure 5 shows that an octave wide pre-whitening system loses between 1 

 and h db in output SNR compared to an Eckart "matched" system for relative 

 signal slopes between -Sdb/oct and -l8db/oct. 



20 



