Abstract

Bioimpedance measurements are useful for determining a variety of biological conditions. By accounting for small impedance variations due to the arterial pulse, the effect of the blood can be studied more closely. The quasi-circulator system presented enables monitoring of pulsatile impedance changes with input frequencies above 1 MHz. The adjustable Rmatch allows for dynamic tuning of the system to increase sensitivity. By tuning Rmatch to be near the match point, the pulsatile signal in the output magnitude can be amplified, and tuning Rmatch to be at the match point causes the pulsatile signal in the output phase to be amplified. The system is tested on discrete circuit elements as well as human subjects, and results are analyzed. Pulsatile variations in the output voltage signal of up to 7 mV and 2.3Â° are demonstrated on human subjects. Tuning Rmatch allows for the pulsatile signal to be increased by more than 4 times.

Degree

College and Department

Ira A. Fulton College of Engineering; Electrical and Computer Engineering

Rights

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