APPARATUS AND METHOD FOR MEASURING PULSE WAVE VELOCITY BY USING BODY COMMUNICATION

대상체의 제 1 부분에 부착되는 적어도 하나의 심전도 전극을 통해 대상체의 심전도 신호를 획득하는 심전도 모듈; 대상체의 제 2 부분에 부착되는 적어도 하나의 생체 임피던스 전극을 통해 대상체의 생체 임피던스 신호를 획득하고, 심전도 모듈로부터 대상체의 인체 통신을 통해 전송되는 심전도 신호를 수신하는 생체 임피던스 모듈; 및 심전도 신호와 생체 임피던스 신호를 이용하여 대상체의 맥파 속도를 측정하는 신호 처리부를 포함하고, 생체 임피던스 모듈은, 심전도 신호와 생체 임피던스 신호를 소정의 샘플링 주파수로 샘플링하여 심전도 신호와 생체 임피던스 신호를 디지털 신호로 변환하고, 디지털 신호로 변환된 심전도 신호와 생체 임피던스 신호를 신호 처리부로 전달하는 변환부를 포함하는 것을 특징으로 하는 본 발명의 일 실시예에 따른 맥파 속도 측정 장치가 개시된다

저잡음 주파수 합성기를 위한 기준 주파수 증폭된 위상 고정 루프와 위상 필터된 조화 고정

학위논문(석사) - 한국과학기술원 : 전기및전자공학전공, 2009.2, [ viii, 66 p. ]This thesis presents several architecture which improve the phase noise performance of frequency synthesizer. To decrease the phase noise of frequency synthesizer which is based on phase locked loop(PLL), reference frequency multiplying technique is used. Three architectures are described to implement the idea. First is to use multi-phase injection locked oscillator(ILO). By using multi-phase ILO, phase errors were compared 8 times within a reference frequency. To use both negative edge and positive edge of the reference signal, reference doubler and differential divider output is proposed. These architectures can reduce the phase noise from both charge pump and $\Delta - \Sigma$ modulator noise at the same time. The simulation results shows that proposed architecture has a good phase noise reduction performance. In addition, direct frequency synthesizer is proposed. This architecture can overcome the disadvantages of direct digital frequency synthesizer(DDFS) by using phase filter and injection locking oscillator. These architectures were implemented in $0.13 \mu m$ CMOS process.한국과학기술원 : 전기및전자공학전공

유헬스를 위한 바이오 임피던스 기반의 바이탈 신호 센서

학위논문(박사) - 한국과학기술원 : 전기및전자공학과, 2014.2, [ viii, 79 p. ]Cardiovascular disease is a general term used to describe disorders that can affect heart and blood vessels systems. Most cardiovascular diseases reflect chronic conditions that develop or persist over a long period of time. In this thesis, vital signs such as heart rate, pulse wave velocity, respiration, body temperature is measured from the electrical properties of human body. Bio-impedance method is a good candidate for the future hand-held health monitoring devices since it is simple, inexpensive and noninvasive. Bio-impedance plethysmography is usually associated with volume changes due to the heartbeats and respiration. Classically, pulse wave velocity and respiration are measured using transducer such as laser, ultrasonic and capacitive sensor that convert signal from mechanical movement to electrical charge flow. In this thesis, respiration measuring methods are presented. Respiration monitoring in everyday life enables the early detection of the disease and disorders that can suddenly manifest in a life threatening episode. Suggested methodology monitor the body volume change in order to capture the respiration rate. In addition, the signal quality is analyzed according to the position of the electrodes to find their optimum position. It is also presented that how much air flows when the respiration occurs as well as respiration rate.To measure the pulse wave velocity low power analog front end is designed. It enables that heart rate and pulse wave velocity can both be monitored using only small body area. The proposed switched current-controlled current source is also low power solution removing static power dissipation. This novel method can increase the efficiency which is ratio of the injected current and dissipation current. The sample and hold circuitry is used as a frequency down converter that has sinc filter property. This method can reduce the capacitor size of the filter and save much power. Body channel communication also adapted to remove...한국과학기술원 : 전기및전자공학과