Measuring Depth Profiles of Scattering in the Ocean

LIDAR (laser radar) is used for oceanographic research, and emits a short light pulse whose return echoes are digitized and analyzed to determine the composition and location of underwater objects. This requires a digitizer with high sampling speed, wide bandwidth commensurate with the pulse width, and high dynamic range. What is needed in reality is a 14 bit, 1 Gsample/second (Gs/s) analog-to-digital converter (ADC), which does not yet exist due to shortcomings of the integrated circuit state-of-the-art. Currently the program is using a 100 MHz logarithmic amplifier and a COTS 8 bit, 1 Gs/s ADC PC plug-in board. Phase 1 proposed, and analytically and experimentally validated, the feasibility of employing a novel array of 12 bit COTS ADCs to achieve the desired dynamic range and bandwidth at a sampling speed of 1 Gs/s. The proposed Phase 2 effort will produce three (3) full proof-of-concept prototype PCI-64 digitizer cards for delivery and NOAA evaluation by implementing and refining the multi-ADC architecture validated in Phase 1.