The Design Of Data Acquisition System In Ultrasonic Imaging

Ultrasound imaging has been applied in body examination since the 1940s. And soon developed to the application in observing the heart and fetal activities in the 1970s.Because of its high speed imaging, timely diagnosis, safety, painless and other characteristics, ultrasound imaging is widely used in medical examination and treatment. Its clinical practice has been popular. And it becomes an important component of medical imaging.With the electronic computer, modern signal processing technology, ultrasound imaging system gradually to all-digital direction. All-digital ultrasound imaging technology transforms echo signal into a digital signal in the receiver front-end. The system will accomplish signal delay, combination and signal processing through a dedicated ASIC design system to replace traditional analog processing circuit. the image is more clear, more accurate resolution, and it also raise the quality of ultrasound diagnostic equipment.This paper describes the design of data acquisition circuit in ultrasonic imaging system. The design bases on high speed A/D converter AD9228, which can reach the highest converter rate at 65MSPS. To simplify the A/D interface, the program using the FPGA to achieve LVDS's signal conversion and deserializer, at last achieve the parallel digital signal output. As the A/D conversion rate faster, after data conversion and before the signal arrive the PC, it need a buffer memory. After consider of its storage rates, storage capacity and price among a variety of types of memory, we chose the SDR-SDRAM (Single Data Rate-Synchronous Dynamic Dandom Access Memory). Finally, through the USB serial bus data transmission,the system transfer the data, stored in the SDR-SDRAM, to PC. in order to prepare follow-up imaging.