Subarray delta-sigma beamforming for ultrasonic imaging

We present a beamforming architecture based on subarray processing with non-uniform oversampling 1-bit delta-sigma (/spl Delta//spl Sigma/) modulation. The subarray processing combines conventional phased array and synthetic aperture approaches to form a large aperture using small subarrays thus reducing active channel count. /spl Delta//spl Sigma/-based beamforming improves the efficiency of front-end processing further: oversampling permits precise delaying and single bit data processing simplifies beamforming operation. To reduce the number of firings we use a low beam density associated with the subarray size, and then increase the beam density by lateral interpolation prior to coherent beam summation. Our experimental test results show that the proposed scheme provides high-resolution beamforming while simplifying the front-end.