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CHAPTER IV 

 DPG SOFTWARE 



A. Introduction 



The theory of data analysis and computer software for the 

 original design of the DPG were developed during the drafting and 

 machining stages of the project. The complete theory and software to 

 directly develop the first seven directional Fourier coefficients for 

 a fully functioning A-arm DPG are presented in this chapter. After 

 initial evaluation of the instrument's first sets of field data, it 

 was considered that only one differential pressure gauge on each axis 

 was reliably accurate. Hence the software package, as used at the 

 FRF installation site, analyzes only two orthogonal differential 

 pressure channels along with the absolute signal. The FRF package, 

 then, is an abridged version of the program described herein. It 

 develops only water surface slope in the x and y directions and 

 vertical displacement, and the first five directional Fourier 

 coefficients . 



