62 - 



10. Failure of 3 Differential Channels 



If only the absolute and one differential pressure channels 

 are considered operational, another estimate of the wave direction 

 might be made with a 180 degree ambiguity. With the power spectra of 

 the absolute and differential channels in the form of Equations 4.46 

 through 4.48; 



nn 1 



S (o) , 2 2. 



n n k cos e 



X X 



So that 



cos 



■1^ 



-111/ Vx (4.53) 



k 1/ s (a) 



nn 



or similarly 



■■.V' 



S La) 



n n 



nn 



for some frequency 6. 



