Analysis and Design of a Multiplex, Delay‐and‐Sum (MDAS) Beamformer Architecture to Implement a Fixed‐Focus Receive Beamformer for Portable Ultrasound Imaging Systems

Abstract

A multiplex, delay‐and‐sum (MDAS) architecture is proposed to implement a fixed‐focus receive beamformer such as the first stage of the synthetic aperture sequential beamforming (P‐SASB) and synthetic transmit beams combined with the P‐SASB (STB‐P‐SASB) beamforming methods. The output image of this architecture has a resolution and contrast‐to‐noise ratio (CNR) almost similar to that of the delay‐and‐sum (DAS) architecture. In the analog part of this architecture, there is no need to use any analog memory and in the digital part, the need to use high‐speed memories and interpolation filter is eliminated. In this architecture for each input channel, the power consumption in the mixed‐signal part is increased by approximately 1.14 mW in comparison to that of the DAS architecture. On the other hand, due to the elimination of the power consumption related to the interpolation filter in the digital part, the total power consumption of the MDAS architecture increases by a maximum of 9.2% compared to the DAS architecture. Also, the silicon area required to implement the mixed‐signal part of the MDAS architecture when implementing the first stage of P‐SASB and STB‐P‐SASB beamforming methods is reduced by about 3 times and increased by a maximum of 25%, respectively, compared to that of the DAS architecture.