A sub-nyquist analog front-end with subarray beamforming for ultrasound imaging

Traditional ultrasound imagers suffer from a large data rate between their analog-to-digital converter (ADC) front-end and digital beamforming backend. This high aggregate data rate (typically exceeding 30 Gb/s) is holding back the design of imagers with high transducer counts, such as 2D imaging arrays. Prior work has demonstrated sub-Nyquist sampling techniques in software, which take advantage of the low innovation rate to sample well below the physical bandwidth of the signal. This work demonstrates a PCB-based hardware implementation of a 32-channel analog front-end (AFE) employing sub-Nyquist sampling. We additionally demonstrate a mixer-based subarray beamforming technique that exploits the narrowband nature of the receiver to beamform received signals prior to digitization. Together, these techniques reduce the aggregate data rate by a factor of 43x when compared to a conventional system.