Extensible Beamformer for Portable Imaging Sonar

Q-DOT proposes to develop a unizue, lower-power, low-cost beamformer for portable imaging sonars. The original two chip set will form 100 beams from 100 input channels. A 0.3 cm2 BiCMOS chip comprises a low noise amplifier (LNA), a time-gain control (TGC), an apodizer and a Delta-Signma modulation (ADC) for each channel. A 0.66 cm2 CMOS chip accepts 100 digital input channels and produces 100 digital beams demodulated to baseband. The two chip set is estimated to dissipate a total of 650 mW or 6.5 mW channel when operating with a 500 KHZ carrier. The chip set is extensible to sonar arrays which use 10,000 elements to generate 10,000 beams without additional glue logic or processors. Q-DOT, SonaTech, and Messrs. Freeman and O'Donnell in close cooperation with the Navy, will assess the feasibility of relaizing an extensible beamformer suitable for imaging sonars during Phase I. The same team will realize a functional 100 channel/100 beam chip set in Phase II and evaluate it at a Government facility.