A sphygmomanometer includes a pump for applying variable pressure to a blood vessel, a microphone for sensing oscillation which is produced from the blood vessel being pressurized by the pump, a pressure detecting section for sensing the pressure being applied to the blood vessel, and a Korotkoff sound...http://www.google.sh/patents/US4840181?utm_source=gb-gplus-sharePatent US4840181 - Sphygmomanometer adopting recognition of korotkoff sounds
