From Equations (3.8) and (5.2) we have for a single wave of frequency 

 fo > from a direction Gq that the two-sided 



4- EKP (i a-« (- i. X.J- «, Y;j)) i (< * f„)J 



C,/4J= C.(-U = -|^os(^1r(^, x,j* .«.Y,.))^ 



(5.3) 



describe the elements for the spectral matrix of a single wave. Recall 

 that, in general, C^^ (f ) = Cj^(f) and Qij (f ) = -Qij(7f)' Substituting 

 into Equation (4.16), we get where b^j = [N(N-l)+l'l"-^ = 1/M ,^ ,. 



and f^ > is assumed 



H-< (L 



so, ,.)*/(,. 



^Z A JCOS (ZT! (i X. -^ M X^ ) COS (ilt (Ui3+ M X^ )) -4- 



The choice of bij = 1/M = [N(N-1)+1]"^ and observing that ^ S^ 1= ^^"^"'^ 



19 



