title: DC information preservation for cardiopulmonary monitor utilizing CW Doppler radar.
abstract: Direct conversion RF receivers introduce large DC offsets, reducing the dynamic range of the baseband signal. Coupled with the relatively small time varying signals in human vital sign monitoring using CW Doppler radar, extraction of cardio-pulmonary information becomes difficult. Previous DC offset compensation techniques utilizing AC coupling have proven detrimental to the performance of the system and the integrity of the low-frequency cardiopulmonary signals. A proposed system utilizing digitally controlled voltage feedback and center finding preserves the important DC information for optimal extraction of phase information in the quadrature system.
authors.affiliation: University of Hawai'i at Manoa, USA. avergara@hawaii.edu
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Vergara
authors.forename: Olga
authors.initials: O
authors.lastname: Boric-Lubecke
authors.forename: Victor M
authors.initials: VM
authors.lastname: Lubecke
mesh_terms: D002319:Cardiovascular System / Q000503:physiopathology*; D017076:Computer-Aided Design; D004301:Doppler Effect; D004867:Equipment Design; D006801:Humans; D008872:Microwaves; D008991:Monitoring, Physiologic / Q000295:instrumentation; D011825:Radar / Q000295:instrumentation; D012137:Respiratory System / Q000503:physiopathology*; D012815:Signal Processing, Computer-Assisted