NAFI TR-li|l+0 



Yl, CASE ^: THE BATOLIMITED ECKART FILTER 



The last optimization to be examined arises basically from 

 curiosity: one wonders just how significant the higher frequencies are in 

 the specification of the Eckart filter. In this section, the performance 

 of both the infinite bandwidth Eckart filter and the pre -whitening, band- 

 limited conventional system will be compared to a bandlimited Eckart filter, 

 defined as 



■A. ^ 



. I ill', /<f^|:>tv 



The system output SWR for such a filter fellows from equation 26: 



utilizing the spectral characteristics from equation' 27, 

 where 



1^5 (^)= /- (z//")'"'^ tH Lis) 



and the logarithmic solution for 5 = i" i^ ignored. 



By comparison with equation 29, it can be seen that the ratio of 

 the bandlimited Eckart filter to infinite bandwidth Eckart filter output 

 SNR's is simply to factor in equation 35, i.e.. 



The comparison to the pre -whitening bandlimited conventional system can 

 be rapidly obtained from the following manipulation: 







'0 *> ' ' "^ ^6 



22 



