A bit deeper, the PPG (photoplethysmogram) signal is measured by the user holding sensors on the phone with both hands. Using math I don't understand, the chip

A bit deeper, the PPG (photoplethysmogram) signal is measured by the user holding sensors on the phone with both hands. Using math I don't understand, the chip can then calculate a fairly accurate (within a couple mmHg) blood pressure. There are a couple papers describing the method on the first page of this search: https://encrypted.google.com/search?{google:acceptedSuggestion}oq=how+optical+blood+pressure+detection+works&q=how+optical+blood+pressure+detection+works https://encrypted.google.com/search?{google:acceptedSuggesti...