- 50 - 



where (x^ , y^ ) , (x3,y3), and (x2,y2), (^i tV^) are the knovm positions 

 of the X- and y-axis slope measurements, respectively. 

 Alternatively, the analysis could be carried out with the 

 non-corrected spectra, the directions at each frequency estimated, 

 and the process repeated using spectra corrected by the previously 

 estimated direction to yield continually more accurate directional 

 information. This analysis, however, can correct only for the 

 principal direction. 



Such corrections are assumed small enough to be neglected in 

 the present analysis. For the worst case of small period waves, 

 (say, 3.2 seconds), the phase shift is less than 1 degree. 



D. Program Operation Notes 



1. Introduction 



The FORTRAN analysis program, presented in Appendix F, 

 accesses and analyzes the five raw digitized voltages recieved from 

 the DPG data storage tape. A crude flow chart of the program is 

 shown in Figure IV-2. 



