Originally Published MEM Fall 2008

FROM THE EDITOR

Imaging has been ripe for advances in mixed-signal processing capabilities, either in standard products or as a complete ultrasound receiver front-end. In response, chip makers are changing the way they develop integrated circuits (ICs) for their imaging customers, notes Scott Pavlik. Pavlik is the strategic marketing manager, healthcare segment, for Analog Devices (ADI; Norwood, MA).

ADI, for example, has launched two new products specifically geared toward providing increased performance while minimizing the amount of power needed to operate the ultrasound equipment. Eight-channel ICs are opening up new applications because of their small size, low power needs, and light weight. Moreover, these ICs are providing more flexibility to designers.

"There are many types of probes and their maximum signals range quite a bit. You want to get deep in the body, but then you also want signals very close to the probe at the skin level," explains Pavlik. To compensate for this, he says that it's important that input be adjustable so that it can accept a wide range of signals.

"We're doing a lot of integration, and we're providing the performance improvement," says Pavlik. "These ultrasound devices are being carried around in ambulances, in clinics, and even in hospitals for bedside imaging."

ADI's new ICs—one for cart-based ultrasound systems and one for portable systems—provide programmable serial port interfaces (SPIs). Such programmability puts more flexibility and more options into the hands of designers. You can adjust the gains and the noise level, and you can make trade-offs to optimize for power or performance. You can adjust the filters digitally to match different probe frequencies. Ultrasound suppliers have realized that they can increase their business by increasing the end applications for their systems, Pavlik says. The design of cart-based systems, for example, has traditionally been driven by the different types of probes. With an increased focus on portability, the game has now changed, and the range of applications is changing.

"We've been talking to customers about opening up new applications utilizing both probe technologies and software technologies. The key has been finding a way to cram all of the electronics of a complex system into a small form factor. That's what parts like these enable," says Pavlik.

With ADI's graphical software development tool, designers can optimize the signal processing through the SPI port. There are also settings that can be changed dynamically. "If you're doing continuous wave (CW) Doppler imaging, for example, you're going to be switching between pulse mode and CW Doppler mode. You can shut off channels without any difficulties."

Pavlik says that ultrasound developers would like to use the design of the receive front-end across different platforms. The fact that these new ICs are pin compatible means that they can use a common layout for a cart system, for example, and perhaps even use that for a handheld portable system. Portability is a growing trend in many areas of healthcare, and it is great to see the development of components specifically designed to make such applications a reality.