This thesis addresses design, production, testing and evaluation of a system that measures air pressure inside the cuff and tubing during measurement or simulation of blood pressure. According to our findings, this is a novel method for measuring dynamic pressure in gases. The measurement system uses a high-pressure condenser microphone with an RF principle of converting changes in capacitance into a voltage signal. We investigated condenser microphone theory, different RF microphone implementation techniques and blood pressure measurement methods. Required frequency range of the constructed RF microphone was from 0,5 Hz to 280 Hz with maximum operating pressure of 300 mmHg, both of which were met. By evaluating key metrological characteristics of the RF microphone we determined total expanded measurement uncertainty, which was ± 4,0 mmHg. An LF sound source was built for testing purposes, in order to determine RF microphone frequency response. The results were evaluated using a blood pressure simulator and compared with a reference piezoelectric pressure sensor. Described RF microphone implementation enables traceability of sphygmomanometers and blood pressure simulators to the acoustic pressure realisation by the so-called reciprocal method. The advantage of measuring blood pressure with the help of a microphone compared to piezoresistive sensors is the possibility to measure dynamic pressure more accurately, which is still insufficiently researched area of metrology.
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