How does the BW 300 detect the human blood pressure?

The BW 300 measures with the so called "oscillometric technique", a worldwide known and accepted process since 30 years. Most of the now available devices for measurement use this method. Electronic microprocessors in oscillometric devices calculate blood pressure data from pressure fluctuation (oscillations), which arise from the occuring pulse. Because of the irrelevance of heartbeats for this method, neither a microphone nor a stethoscope is necessary.