• Journal of Sensor Science and Technology
• /
• 제25권1호
• /
• pp.71-78
• /
• 2016

PPG signal measured by pulse oximeter can measure pulse and the oxygen saturation of arterial blood. But the PPG signal is distorted by finger movement or other movement in the body. To detect pulse from the PPG signal with motion artifact, we use band pass filter(BPF), Independent component analysis(ICA) and nonlinear autocorrelation(NAC). BPF is used to remove DC component and high frequency noise in the PPG signal with motion artifacts. ICA is used to separate pulse signal and motion artifact. However, pulse signal separated by ICA have no choice but to accompany signal distortion because pulse signal and motion artifact are not completely independent. So, we use nonlinear autocorrelation to emphasize the pure pulse signal from the distorted signal.

• Proceedings of the KIEE Conference
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.1914-1915
• /
• 2007

The period and strength of the pulse on the radial artery are important physiological factors, and they have been used to diagnosis in both Western and Eastern countries for a long time and has been developed as a unique method of diagnosis at each countries. Recently, there are a lot of systems which can give diagnosis information by recording the pulse wave and analyzing the characteristics of the pulse shape. This study describes the Pulse-Wave Measurement System which is able to measure the pulse wave signal using piezoresistive sensor and the pulse wave signal measured by the developed system is transmitted to a computer on the basis of the USB Driver. It has finally shown the the pulse wave signal measured by the sender is appeared to the host PC in real time. The Pulse-Wave Measurement System used the piezoresistive sensor to measure the pulse wave signal and the differential amplifier(AD620) to amplify the pulse wave signal which is small signal. And it used the ADC to convert analog to digital for the measured analog signal and the interface with a computer. It transmitted the measured pulse signal through USB transmission module to the host computer and Labview tool shows it. This Pulse-Wave measurement system will afford comvenience of detecting pulse wave to user related to oriental medicine.

• Journal of Sensor Science and Technology
• /
• 제26권2호
• /
• pp.141-147
• /
• 2017

A pressure sensor in pulse measurement system is a core component for precisely measuring the pulse waveform of radial artery. A pulse sensor signal that measures the pulse wave in contact with the skin is affected by the temperature difference between the ambient temperature and skin surface. In this study, we found experimentally that the signal changes of the pressure sensors and a temperature sensor were caused by the temperature of the wrist surface while the pressure sensor was contacted on the skin surface for measuring pulse wave. To observe the signal change of the pulse sensor caused by temperature increase on sensor surface, Peltier device that can be kept at a set temperature was used. As the temperature of Peltier device was kept at $35^{\circ}C$ (the maximum wrist temperature), the device was put on the pulse sensor surface. The temperature and pressure signals were obtained simultaneously from a temperature sensor and six pressure sensors embedded in the pulse sensor. As a result of signal analysis, the sensor pressure was decreased during temperature increase of pulse sensor surface. In addition, the signal difference ratio of pressure and temperature sensors with respect to thickness of cover layer in pulse sensor was increased exponentially. Therefore, the signal of pressure sensor was modified by the compensation equation derived by the temperature sensor signal. We suggested that the thickness of cover layer in pulse sensor should be designed considering the skin surface temperature.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제21권6호
• /
• pp.8-15
• /
• 2013

Wide range frequency pulses occur in a car crash test. Until now, low frequency under 400Hz has been used to determine an airbag deployment criteria. Also, FIS (Front Impact Sensor) has been used to detect the crash pulse in early stage. Nowadays, technology to determine an airbag delpoyment criteria by using a high frequency crash pulse without FIS is being focused on. In this paper, the signal transmissibility of high frequency pulse for two different cars was studied. Also, signal transfer test of high frequency pulse was done by using a high speed ball impact. Signal runtime of the frontal impact is compared with that of the side impact. The signal transmissibility difference due to the car structure difference was discussed and structure change for improving the signal transmissibility was proposed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 한국해양정보통신학회 2011년도 추계학술대회
• /
• pp.353-356
• /
• 2011

A Signal Receiving system to collect and analyze RF signals should be verified under simulated RF signal environment prior to verification on operation in fields and tested by using simulated RF signals in order to estimate its electrical performance. Generally, typical Signal Receiving system can measure, analyze frequency, pulse modulation, scan modulation, phase modulation on pulse, frequency modulation on pulse etc on RF signals. These RF signals should be generated from simulated RF sources in laboratory. Also the simultaneous RF signals should be simulated on laboratory. This paper describes the results of studying effective simulated RF signal source generation, the methods of the precise RF test signal generation in consideration of operational scenario.

• Journal of Biomedical Engineering Research
• /
• 제35권6호
• /
• pp.234-241
• /
• 2014

This study was designed to investigate the effects of stimulation intensity and inter-electrode distance on the parameters of the measured sensory nerve signal. 30 healthy subjects participated in this study. Sensory nerve signals were elicited by four different pulse amplitudes, i.e., 3, 6, 9, 12 mA, with the pulse width fixed at $500{\mu}s$. The sensory nerve signals elicited by the four different pulse amplitudes were measured by four different inter-electrode distances (20, 30, 40, and 50 mm). We extracted four parameters (pulse amplitude, pulse width, pulse area, and latency time from stimulation) from the sensory nerve signals. The measured pulse amplitude and pulse width were increased when the measuring inter-electrode distance was increased while the stimulating pulse amplitude was fixed. The measured pulse amplitude was saturated with the stimulating pulse amplitudes of over 6 mA while measuring inter-electrode distance. Under the same condition, measured pulse width was increased, and sensory nerve signal was initiated early. Sensory nerve signals, specially those of pulse amplitude, were distorted by a differential amplification method that commonly measures the human body signal. The experimental results indicate that the differential amplification method is required to be replaced when measuring nerve signals. Our observations suggested that the hyperpolarization of the action potential of the sensory nerve signal for preventing distortion could be used to clarify the correlation between the parameters of the sensory nerve signals and quantification of sensations.

• Journal of the Korea Institute of Military Science and Technology
• /
• 제12권5호
• /
• pp.652-659
• /
• 2009

To analyze and verify the performance of a pulse radar without the real target data, there is a need to make the simulated signal which is similar to the received signal of the real target. In this paper, a method of the received signal generation for the pulse radar is proposed to solve the above need. The user-made scenarios are used to model the fast and small target and the clutter data based on the ground environment. These data are transformed into the electric signal using the proposed method. The efficiency of the proposed method is proved by comparing the signal of a field test with the simulated signal.

• Journal of the Korean Magnetic Resonance Society
• /
• 제26권4호
• /
• pp.51-58
• /
• 2022

The baseline flattened NMR spectrum has been achieved by several methodologies including pulse manipulation with a series of phase cycling. The background signal inherent in the probe is also main source of baseline distortion both in solution and solid NMR. The simple direct polarization with 90° pulse flipping the magnetization from the z-axis onto the receiver coil requires the strong rf pulse enough to encompass the wide frequency range to excite the resonance of interest nuclei. Albeit the perfect polarization 90° pulse, the signal from the unwanted magnetic fields such as background signal can not be completely suppressed by suitable phase cycling. Moreover, slowly baseline wiggling signal from the low 𝛾 nuclei is not easy to eliminate with multiple pulse manipulation. So there is still need to contrive the new scheme for that purpose in an adroit manner. In this article new triple pulse excitation schemes for TIP and modified DEPTH pulse sequence are analytically examined in terms of arbitrary phase and flip angle of pulse. The suitable phase cycling for these pulse trains is necessary for the good sensitivity and resolution of the spectrum. It is observed that the ¹³C sensitivity TIP experiment is almost equal to the CP/MAS with modified DEPTH sequence, both of which are applicable to both solid and solution state NMR.

• The Journal of the Acoustical Society of Korea
• /
• 제16권2호
• /
• pp.5-9
• /
• 1997

In this paper, when we use the chirp signal as input signal of ultrasonic signal system the technique for determining the bandwidth of the chirp signal that maximizes the amplitude of the compressed ultrasonic echo signal has been studied. In ultrasonic signal processing systems, the signal-to-noise ratio of the echo signal can be too low due to damping and scattering of the ultrasonic wave during transmission. Method of pulse compression using chirp signal is a means to increase the signal-to-noise ratio in ultrasonic pulse-echo systems. Simulation and experimental results showed that the output signal of ultrasonic system was increased by pulse width of chirp signal and the optimum-bandwidth of the chirp signal was 1.15 times larger than the bandwidth of the ultrasonic system.

• Journal of Navigation and Port Research
• /
• 제29권4호
• /
• pp.341-347
• /
• 2005

A unique technique to extract the phase in time domain is proposed in order to measure the time parameters such as speed and depth by transmitting sound and electric waves. In the signal analysis processing, the phase of pulse signal can be transformed and digitalized with local data in real time without the effect of direct current bias and Nyquist limits. This method is sensitive to base frequency of pulse signal with high spacial resolution and is effective to compare two signals which have different forms. It is expected that the phase analysis technique will be applied to the measurement of the speed and depth accurately by ultrasonic pulse signal in water.