An Ethernet-Based Ultrasound Signal Processor

In many ultrasound non destructive evaluation (NDE) applications, the transducers are located far away from the evaluation site. Traditionally, low level analog signals are sent over long lines to the ultrasound instrument, which give rise to noise problems. In this work a different approach is followed by integrating in a single FPGA, digital processing functions together with an Ethernet link for several ultrasound channels. These functions include a set of digital signal processing functions to improve the information content of the output data stream: linear and non linear digital filtering, envelope extraction, multiple gates with programmable thresholds and data compression. Following the concept of system-on-a-chip, a processor is integrated in the FPGA. Although it is not involved in signal processing, it performs most of the internal and external communications and eases system upgrading. The Ethernet link implements the TCP/IP stack and allows networking for bidirectional communication with a host. Implementation in the FPGA hardware allows achieving high data rate transfers. Data packets are formatted in frames, which include information on status, position, peaks and processed data.