Abstract: In this study, an improved heterodyne demodulation quartz-enhanced photoacoustic spectroscopy (IHD-QEPAS) gas sensor is demonstrated, employing an erbium-doped fiber (EDF)-ring laser for the ...

Abstract: Doppler radar systems can demonstrably provide accurate measurement of physiological motion for sedentary and partially sedentary subjects. In this research, quadrature and single-channel ...