| Summary: | 碩士 === 國立交通大學 === 電控工程研究所 === 100 === The main research is the Doppler principle. To establish 2.4G and 4 ~ 6GHz non-contact radar transceiver, used to detect human respiration and heartbeat. Due to respiration and heartbeat will produce dynamic changes,resulting in phase modulation on reflected signal. In the receiver use synchronize demodulation, the microwave signal transfer to baseband directly and then to separate the respiration and heartbeat in Labview digital filter. Respiration uses high-pass filter( 0.15Hz ); Heartbeat uses band-pass filter (0.9~1.5Hz).That accumulate 20 seconds of data to do the fast Fourier transform.In the frequency domain, to capture the frequency in maximum peak to display per minute number of heartbeats and respiration. The operational frequency have no certification ISM band (2.4G, 5.8G), due to the lower frequency have longer wavelength and the lower attenuation that have greater output power with component characteristics in lower frequency. It can be applied to indoor and outdoor monitoring for long rang covered condition. In order to measure the small amplitude of heartbeat that need short- wavelength to increase receive sensitivity. For this question, the paper design switchable multi- frequency system, to select the appropriate frequency on the different environment. In addition to radar systems, the 2.4GHz and broadband yagi antenna are maked, the plane Yagi architecture provides a complete integration, small size and better directivity. While the 2.4G system also connects the circulator that make receiver and transmitter just share an antenna. The compare of accuracy used commercially Oxygen machine for different subject, distance and shelter in different frequency and monostatic, bistatic radar architecture. Finally test radar range and the effects of respiration harmonics that verify the usefulness of clinical cardiopulmonary testing and remote detection.
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