sequence of random phases 6„ are specified over the interval from to 2n. Then the 

 Fourier amplitudes are found from the relation 



n Y ry^ n^ n 



(4.7) 



given a discrete target spectrum 5^ as a function of angular firequency (i)„. The final step 

 is to determine the discrete time series by inverse Fourier transforming the amplitudes 

 and phases. This method provides a very close match with the target peak frequency 

 and the spectral shape. 



For these initial test series, two wave board drive signals were generated 

 corresponding to two water depths. The design conditions for wave generation are 

 listed in Table 4.2. Note that the gain is generator specific but provides a crude judge of 

 the energy levels because gain is roughly linearly related to wave height. 



Table 4.2 



Wave Generation in Initial Damage 



Experiment 



Wave 



Generator 



Depth 



cm 



Peak 

 Period 



sec 



Gain 



as percent of 



maximum 



1 



112.7 



2.50 



50 



2 



112.7 



2.50 



70 



3 



112.7 



2.50 



90 



4 



116.5 



2.50 



50 



5 



116.5 



2.50 



70 



6 



116.5 



2.50 



90 



63 



