ILLUSTRATIONS (Continued) 



Figure Page 



6. Photograph of Digital Wave Staff for Field Use II 



7. Schematic Diagram of Output Wave Forms for the Digital 



Wave Staff 12 



8. Logic Diagram of Electronics Package for Digital Wave Staff 13 



9. Diagram of 16x8 Logic Matrix for Digital Wave Staff 

 Electronics Package 14 



10. Photograph of Mini-Digital Wave Staff for Laboratory Use . . 16 



11. Block Diagram of Period Counter for Use with Vibrating- 



Wire Pressure Sensor 17 



12. Underwater Photograph of Synchronous Timing Lights 19 



13. Resolution (Tp) and RMS Error (/m/n) as Functions of the 

 Sampling Interval At, the Number of Data Points (n) and 



the Number of Lags (m) 23 



14. Spectra of Waves Measured Simultaneously in the Laboratory 

 Using Mini-Digit Wave Staffs as Sensors 25 



15. Wave Spectra and Cross-Spectral Analysis for Two Members 

 of an Array of Digital Wave Staffs, El Moreno, Gulf of 



Ca 1 if'ornia, Mexico 28 



16. Schematic Diagram of Array for Measuring Nearshore 



Wave Modes 31 



17. Schematic Diagram of Instrument Layout for Investigating 



the Mechanics of Sand Transport 32 



18. Orbital Motion and Sand Suspension Measured off the Scripps 

 Institution Pier Employing the Instrument Layout Shown in 

 Figure 17 34 



