https://news.ncsu.edu/2020/08/new-ultrasound-approach/

“Conventional ultrasound devices have a receiver that detects ultrasonic waves and converts them into an electrical signal, which is then sent to a computer that processes the signal and converts it into an image,” says Xiaoning Jiang, co-corresponding author of a paper on the work and a Duncan Distinguished Professor of Mechanical and Aerospace Engineering at NC State. “We’ve created a device that effectively eliminates the electrical signal processing altogether.”