Blood pressure is an important physiological parameter to be monitored. For several medical conditions, it is important to quickly know the rise or fall in blood pressure. While researchers are working to evolve a reliable continuous noninvasive arterial pressure (CNAP) monitoring devices based on sophisticated signal processing with various technologies including Peñáz principle & pulse wave velocity (PWV); we present a very simple system to continuously indicate the variations in blood pressure. Using the typical shapes of the pulse wave obtained by infra-red photoplethysmography (PPG) from brachial and radial artery, we estimate the changes in pulse transit time (PTT). This change is effected onto a change in tone of an audio beep. The simple circuit was assembled and tested. The details are presented in the paper.
Key words: Pulse wave velocity, Pulse transit time, Blood pressure, Differential amplifier, Photoplethysmography
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