A Strict-Time Distributed Architecture for Digital Beamforming of Ultrasound Signals

This paper presents a strict timing-coherent digital signal processing architecture. The main requirement is that programmable events can be produced within predictable time intervals with tight accuracy (timing errors < 1 ns). This characteristic is essential to ultrasound beamforming. The followed approach defines a modular and scalable architecture (AMPLIA), which is configured as a multibranch pipeline. This arrangement guarantees timing coherence along all the system, independent of the number of processing modules. An important element of the architecture is the interface and control unit (ICU), which decouples the asynchronous communication channel with a host computer to the strictly timing-coherent domain of the signal processing system. Furthermore, in the beamforming application, several elements have a great impact on system timing resolution, particularly when dynamic focusing is involved. This paper addresses the issues of coded excitation, analog-to-digital (A/D) conversion, and signal interpolation in achieving dynamic focusing by progressive focusing correction with processing rates of several gigasamples per second and tight timing accuracy.