Oversampled delta-sigma beamformer with modified zone-based dynamic focusing

Ultrasonic beamformation based on delta-sigma (DeltaSigma) modulation has been proposed to dramatically reduce the size and complexity of the system front-end electronics. In this paper, we present a modified zone-based dynamic focusing technique to substantially reduce the workload for delay computational in a DeltaSigma beamformer. Further cost reduction thereby is achievable through savings on the hardware resources dedicated to the real-time delay computation. By accounting for the group delay of the reconstruction filter, the proposed technique can also eliminate the image artifacts due to the signal distortion related to the delay update in dynamic receive focusing. Both Field II simulation and real ultrasound data emulation are carried out to illustrate and qualify its effectiveness. The associated structure for implementation of the proposed technique is also provided