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Accurate continuous measurement of respiratory displacement using continuous wave Doppler radar requires rigorous management of dc offset which changes when a subject changes distance from the radar measurement system. Effective measurement, therefore, requires robust dynamic calibration which can recognize and compensate for changes in the nominal position of a subject. In this paper, a respiratory displacement measurement algorithm is proposed which can differentiate between sedentary and non-sedentary conditions and continuously adapt to provide long-term monitoring of a subject’s sedentary respiration. Arctangent demodulation is an effective means of quantifying continuous displacement using a quadrature Doppler radar, yet it depends on accurate identification of dc offset and dc information contributions in the radar I-Q arc with the subject in a particular position. The dynamic calibration method proposed here is demonstrated to differentiate between sedentary and non-sedentary conditions for six subjects to produce accurate sedentary respiration measurements even when the subject arbitrarily changes position, once the appropriate thresholds are established for the measurement environment.
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Measurement of the Complex Human Atrial-Ventricular Motions using Contact-Based Doppler Radar
Contact-based cardiac motion detection using Quadrature Doppler radar faces a challenge of the I/Q-formed non-arc constellation. In this work, a hypothesis is brought forward that such complicated constellation originates from not one, but two moving targets. The dual-motion model may very well explain that contact-based Doppler radar detects both atrium and ventricle motions during cardiac cycles. In this work, dual-motion simulation and phantom measurements are presented, verifying that the atrial-ventricular motions are the reason that I/Q baseband signals transcribe a complex non-arc constellation. It offers the first evidence that contact-based Doppler radar measures actual heart motion.
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- Award ID(s):
- 1660253
- PAR ID:
- 10129096
- Date Published:
- Journal Name:
- 2019 IEEE 20th Wireless and Microwave Technology Conference (WAMICON)
- Page Range / eLocation ID:
- 1 to 5
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/WAMICON.2019.8765441
