• Title/Summary/Keyword: Power signal

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Simulation and Evaluation of ECT Signals From MRPC Probe in Combo Calibration Standard Tube Using Electromagnetic Numerical Analysis (전자기 수치 해석을 이용한 Combo 표준 보정 시험편의 MRPC Probe 와전류 신호 모사 및 평가)

  • Yoo, Joo-Young;Song, Sung-Jin;Jung, Hee-Jun;Kong, Young-Bae
    • Journal of the Korean Society for Nondestructive Testing
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    • v.26 no.2
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    • pp.90-98
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    • 2006
  • Signals captured from a Combo calibration standard tube paly a crucial role in the evaluation of motorized rotating pancake coil (MRPC) probe signals from steam generator (SG) tubes in nuclear power plants (NPPs). Therefore, the Combo tube signals should be consistent and accurate. However, MRPC probe signals are very easily affected by various factors around the tubes so that they can be distorted in their amplitudes and phase angles which are the values specifically used in the evaluation. To overcome this problem, in this study, we explored possibility of simulation to be used as a practical calibration tool far the evaluation of real field signals. For this purpose, we investigated the characteristics of a MRPC probe and a Combo tube. And then using commercial software (VIC-3D) we simulated a set of calibration signals and compared to the experimental signals. From this comparison, we verified the accuracy of the simulated signals. Finally, we evaluated two defects using the simulated Combo tube signals, and the results were compared with those obtained using the actual field calibration signals.

Field Test and Performance Verification of On-board Oriented Train Control System (차상중심 열차제어시스템의 현장시험을 통한 성능검증)

  • Baek, Jong-Hyen
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.8
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    • pp.5513-5521
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    • 2015
  • There is an operational efficiency problem about wayside equipment applied to the domestic low-density branch as the equipment has been installed and operated similarly in the mainline. On-board oriented train control system, which has been developed for train safety and operation efficiency, ensures safe train operation without expensive ground control signal devices. Such system consists of on-board control system, wayside control system, and local control system. In this paper, the details of tests such as suitability test, communication test, and interface test are described by installing the on-board control system and wayside control system in field. Installation tests include checking power, voltage, cable connection, LED status, etc. Field applicability of the developed system is also verified through the dynamic operation tests with diverse scenarios, which are performed on the virtual line similar to the real environment including switch machine and level crossing gate. Dynamic operation tests were conducted for total 7 scenarios, and several tests were repeated for each scenario. The elapsed time for each operation was computed by analyzing main process log, and we could check that each operation was accomplished within several seconds. Furthermore, the developed system was verified through field test with an accredited institute, and testing certificates were issued.

1V 1.6-GS/s 6-bit Flash ADC with Clock Calibration Circuit (클록 보정회로를 가진 1V 1.6-GS/s 6-bit Flash ADC)

  • Kim, Sang-Hun;Hong, Sang-Geun;Lee, Han-Yeol;Park, Won-Ki;Lee, Wang-Yong;Lee, Sung-Chul;Jang, Young-Chan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.9
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    • pp.1847-1855
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    • 2012
  • A 1V 1.6-GS/s 6-bit flash analog-to-digital converter (ADC) with a clock calibration circuit is proposed. A single track/hold circuit with a bootstrapped analog switch is used as an input stage with a supply voltage of 1V for the high speed operation. Two preamplifier-arrays and each comparator composed of two-stage are implemented for the reduction of analog noises and high speed operation. The clock calibration circuit in the proposed flash ADC improves the dynamic performance of the entire flash ADC by optimizing the duty cycle and phase of the clock. It adjusts the reset and evaluation time of the clock for the comparator by controlling the duty cycle of the clock. The proposed 1.6-GS/s 6-bit flash ADC is fabricated in a 1V 90nm 1-poly 9-metal CMOS process. The measured SNDR is 32.8 dB for a 800 MHz analog input signal. The measured DNL and INL are +0.38/-0.37 LSB, +0.64/-0.64 LSB, respectively. The power consumption and chip area are $800{\times}500{\mu}m2$ and 193.02mW.

Performance Enhancement of Algorithms based on Error Distributions under Impulsive Noise (충격성 잡음하에서 오차 분포에 기반한 알고리듬의 성능향상)

  • Kim, Namyong;Lee, Gyoo-yeong
    • Journal of Internet Computing and Services
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    • v.19 no.3
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    • pp.49-56
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    • 2018
  • Euclidean distance (ED) between error distribution and Dirac delta function has been used as an efficient performance criterion in impulsive noise environmentsdue to the outlier-cutting effect of Gaussian kernel for error signal. The gradient of ED for its minimization has two components; $A_k$ for kernel function of error pairs and the other $B_k$ for kernel function of errors. In this paper, it is analyzed that the first component is to govern gathering close together error samples, and the other one $B_k$ is to conduct error-sample concentration on zero. Based upon this analysis, it is proposed to normalize $A_k$ and $B_k$ with power of inputs which are modified by kernelled error pairs or errors for the purpose of reinforcing their roles of narrowing error-gap and drawing error samples to zero. Through comparison of fluctuation of steady state MSE and value of minimum MSE in the results of simulation of multipath equalization under impulsive noise, their roles and efficiency of the proposed normalization method are verified.

Development of a Raman Lidar System for Remote Monitoring of Hydrogen Gas (수소 가스 원격 모니터링을 위한 라만 라이다 시스템 개발)

  • Choi, In Young;Baik, Sung Hoon;Park, Nak Gyu;Kang, Hee Young;Kim, Jin Ho;Lee, Na Jong
    • Korean Journal of Optics and Photonics
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    • v.28 no.4
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    • pp.166-171
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    • 2017
  • Hydrogen gas is a green energy sources because it features no emission of pollutants during combustion. But hydrogen gas is very dangerous, being flammable and very explosive. Hydrogen gas detection is very important for the safety of a nuclear power plant. Hydrogen gas is generated by oxidation of nuclear fuel cladding during a critical accident, and leads to serious secondary damage in the containment building. This paper discusses the development of a Raman lidar system for remote detection and measurement of hydrogen gas. A small, portable Raman lidar system was designed, and a measurement algorithm was developed to quantitatively measure hydrogen gas concentration. To verify the capability of measuring hydrogen gas with the developed Raman lidar system, experiments were carried out under daytime outdoor conditions by using a gas chamber that can adjust the hydrogen gas density. As results, our Raman lidar system is able to measure a minimum density of 0.67 vol. % hydrogen gas at a distance of 20 m.

Development of On-axis Raman Lidar System for Remotely Measuring Hydrogen Gas at Long Distance (원거리 수소 가스 원격 계측을 위한 On-axis 라만 라이다 장치 개발)

  • Choi, In Young;Baik, Sung Hoon;Lim, Jae Young;Cha, Jung Ho;Kim, Jin Ho
    • Korean Journal of Optics and Photonics
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    • v.29 no.3
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    • pp.119-125
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    • 2018
  • Hydrogen gas is an important and promising energy resource that has no emissions of pollutants during power generation. However, hydrogen gas is very dangerous because it is colorless, odorless, highly flammable, and explosive at low concentration. Conventional techniques for hydrogen gas detection are very difficult for measuring the hydrogen gas distribution at long distances, because they sample the gas to measure its concentration. Raman lidar is one of the techniques for remotely detecting hydrogen gas and measuring the range of the hydrogen gas distribution. A Raman lidar system with an on-axis optical receiver was developed to improve the range of hydrogen gas detection at long distance. To verify the accuracy and improvement in the range of detecting the hydrogen gas, experiments measuring the hydrogen gas concentration are carried out using the developed on-axis Raman lidar system and a gas chamber, to prevent explosion of the hydrogen gas. As a result, our developed on-axis Raman lidar system can measure a minimum hydrogen gas concentration of 0.66 volume percent at a distance of 50 m.

3-D Simulation of Pyroelectric IR Sensor and Design of Optimized Peripheral Circuit (초전형 적외선 센서의 3차원 모델링과 최적화된 주변회로 설계)

  • Min, Kyung-Jin;Kang, Seong-Jun;Yoon, Yung-Sup
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.37 no.10
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    • pp.33-41
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    • 2000
  • Pyroelectric characteristics such as voltage responsivity, noise equivalent power and detectivity are modeled 3-dimensionaly considering th interaction of each parameters. Also, the circuit is designed to set up the frequency band width and the signal amplification of the pyroelectric IR sensor. The case of low frequency region shows that the voltage response increases with the independence of the sensor area as the thickness decreases. In the high frequency region, it is found that the voltage response with the load resistor of 20$G{\Omega}$ increases with the independence of the sensor thickness as the sensor area decreases. In the low frequency region, the detectivity becomes excellent at th load resistor of 20$G{\Omega}$, the sensor area larger than $4{\times}10^{-10}m^2$ and the sensor thickness thinner than $1{\times}10^{-5}m$, while, in the high frequency region, it shows high value at the sensor thickness thinner than $1{\times}10^{-5}m$ and the sensor area smaller than $2{\times}10^{-10}m^2$ with the independence of the load resistor. In the circuit design, quasi-boot-strap circuit is employed, in which a single op-amp is connected to the drain of JFFT. Desirable frequency band width, amplification rate and the remarkable drop of noise of about 56% from that of conventional circuits with double op-amps are obtained.

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A Design of Novel Instrumentation Amplifier Using a Fully-Differential Linear OTA (완전-차동 선형 OTA를 사용한 새로운 계측 증폭기 설계)

  • Cha, Hyeong-Woo
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.1
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    • pp.59-67
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    • 2016
  • A novel instrumentation amplifier (IA) using fully-differential linear operational transconductance amplifier (FLOTA) for electronic measurement systems with low cost, wideband, and gain control with wide range is designed. The IA consists of a FLOTA, two resistor, and an operational amplifier(op-amp). The principal of the operating is that the difference of two input voltages applied into FLOTA converts into two same difference currents, and then these current drive resistor of (+) terminal and feedback resistor of op-amp to obtain output voltage. To verify operating principal of the IA, we designed the FLOTA and realized the IA used commercial op-amp LF356. Simulation results show that the FLOTA has linearity error of 0.1% and offset current of 2.1uA at input dynamic range ${\pm}3.0V$. The IA had wide gain range from -20dB to 60dB by variation of only one resistor and -3dB frequency for the 60dB was 10MHz. The proposed IA also has merits without matching of external resistor and controllable offset voltage using the other resistor. The power dissipation of the IA is 105mW at supply voltage of ${\pm}5V$.

Developing an On-Line Monitoring System for a Forest Hydrological Environment - Development of Hardware - (산림수문환경(山林水文環境) 모니터링을 위(爲)한 원거리(遠距離) 자동관측(自動觀測)시스템의 개발(開發) - 하드웨어를 중심(中心)으로 -)

  • Lee, Heon Ho;Suk, Soo Il
    • Journal of Korean Society of Forest Science
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    • v.89 no.3
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    • pp.405-413
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    • 2000
  • This study was conducted to develop an on-line monitoring system for a forest hydrological environment and its meteorological condition, such as temperature, wind direction and speed, rainfall and water level on V-notch, electrical conductivity(EC), potential of hydrogen(PH) by the motor drive sensor unit and measurement with a single-chip microprocessor as controller. These results are summarized as follows ; 1. The monitoring system consists of a signal process unit, motor drive sensor unit, radio modem unit and power supply. 2. The motor drive sensor unit protects the sensor from swift current or freezing and can constantly maintain fixed water level during measurements. 3. This monitoring system can transfer the data by radio modem. Additionally, this system can monitor hydrological conditions in real time. 4. The hardware was made of several modules with an independent CPU. They can be mounted, removed, repaired and added to. Their function can be changed and expanded. 5. These are the result of an accuracy test, the values of temperature, EC and pH measured within an error range of ${\pm}0.2^{\circ}C$, ${\pm}1{\mu}S$ and ${\pm}0.1pH$ respectively. 6. This monitoring system proved to be able to measure various factors for a forest hydrological environment in various experimental stations.

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A Variable-Gain Low-Voltage LNA MMIC Based on Control of Feedback Resistance for Wireless LAN Applications (피드백 저항 제어에 의한 무선랜용 가변이득 저전압구동 저잡음 증폭기 MMIC)

  • Kim Keun Hwan;Yoon Kyung Sik;Hwang In Gab
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.10A
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    • pp.1223-1229
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    • 2004
  • A variable-gain low-voltage low noise amplifier MMIC operating at 5GHz frequency band is designed and implemented using the ETRI 0.5$\mu\textrm{m}$ GaAs MESFET library process. This low noise amplifier is designed to have the variable gain for adaptive antenna array combined in HIPERLAN/2. The feedback circuit of a resistor and channel resistance controlled by the gate voltage of enhancement MESFET is proposed for the variable-gain low noise amplifier consisted of cascaded two stages. The fabricated variable gain amplifier exhibits 5.5GHz center frequency, 14.7dB small signal gain, 10.6dB input return loss, 10.7dB output return loss, 14.4dB variable gain, and 2.98dB noise figure at V$\_$DD/=1.5V, V$\_$GGl/=0.4V, and V$\_$GG2/=0.5V. This low noise amplifier also shows-19.7dBm input PldB, -10dBm IIP3, 52.6dB SFDR, and 9.5mW power consumption.