Teardown: Inside the art of pulse oximetry

The second feature lets the Radical-7 connect to third-party monitors and regenerate the physiological signal. "Existing operating rooms already have patient-monitor devices; all they need is our technology," said Sampath. Using a feature called SatShare, the station can display the captured measurements on third-party monitors, which in turn can be integrated into a hospital's information management system. This also allows patients' physiological measurements to go directly into their electronic medical records.

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To do this, the docking station relies on yet another Sharc processor. This time it's the lower-cost ADSP-21065L, a general-purpose, programmable 32-bit DSP with fixed- or floating-point capability (get quote). The 21065L is supported by 8 Mbits of boot-sector flash from AMIC Technology (A29L008AUV) and 2 Mbits of SRAM from Alliance Memory (AS6C2008).

FDA approvals
As a medical system, the Radical-7 had to square with IEC as well as FDA regulations. "When we introduced this in 2005, we had to pass all the leakage current, EMC and isolation standards as part of IEC [certification]," said Sampath. Masimo accomplished that by "sticking to fundamentals" with respect to layout, ensuring that clocks had adequate ground plane protection and that trace paths for high-power signals were appropriately managed.

Despite Masimo's system-design prowess, it's worth noting that the company commonly licenses its MX-1 technology to other medical system manufacturers.