• Title/Summary/Keyword: Frequency Deviation

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A Study on the Allowable Deviation for the Measured Level of the Impact Sound Insulation Performance (바닥충격음 차음성능평가에 있어서 측정 레벨의 허용오차에 관한 연구)

  • 장길수;김선우
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.10a
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    • pp.222-226
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    • 1997
  • The reproducibility of measured level is a prior condition for the reliable assessment of the sound insulation performance. To review the reproducibility of impact sound level, 20 floors were selected in highrise apartment house, and then impact sound levels of two kinds of typical floors were measured with 10 times in each receiving point. The impact sound insulation class values were derived with a standard tapping machine and bang machine. Inspection of the result showed that smaller scale of the room caused to lower the reproducibility and that the higher values of standard deviation in lower frequency caused to deteriorate the reliability of assesment. Thus to enhance the reproducibility of the impact sound insulation class, greater allowable deviation of measured level is required in lower frequency than in higher one.

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Frequency Responses of Ambulatory ECG Systems and Their Correction by a Compensation Circuit

  • Iwao, K.;Yokoi, A.;Suzuki, S.;Goto, T.;Doniwa, K.;Okajima, M.
    • Journal of Biomedical Engineering Research
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    • v.11 no.1
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    • pp.13-18
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    • 1990
  • Frequency responses of ambulatory electrocardiogram systems were measured. Phase shift was assessed by our improved Wagner's method. The characteristics of the systems were found much worse than that of ordinary ECG equipment both in gain and phase responses. The decay of -3dB in amplitude observed in 0.2Hz and the lead of 45 dog in phase was observed in 0.6Hz. In order to investigate which of these 2 responses play major role in generating false S -T deviation, mathe- matical filters were Composed in a computer and actual ECGs were fed. The false S-T deviation were found to be caused mostly by enormous lead in phase, and then, the compensation circuit to diminish the lead in phase was inserted in the commercial systemes. The compensated systems showed no false deviation in S-T segment.

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Frequency modulation of a waveguide cavity cw IMPATT diode oscillator (도파관캐비티를 사용한 임팻다이오드 발진기의 주파수변조특성)

  • 윤현보
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.12 no.6
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    • pp.1-4
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    • 1975
  • This paper dells with the impedance variations of the IMPATT diode depending upon the small a.c. coomponent superimposed on the d.c. bias. The frequency deviation of the modulated wave is measured using a carrier null method on microwave spectrum analyser. Frequency modulation is achieved by the weack a.c. signal superimposed on the d.c. bias. The bandwidth rapidly increase with increasing modulation signal magnitude for constant modulation frquency and slightly decrease with decreasing modulation frequency for constant modulation signal magnitude.

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A Simple Bridge Resistance Deviation-to-Frequency Converter for Intelligent Resistive Transducers (지능형 저항성 변환기를 위한 간단한 브리지 저항 편차-주파수 변환기)

  • Lee, Po;Chung, Won-Sup;Son, Sang-Hee
    • Journal of IKEEE
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    • v.12 no.3
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    • pp.167-171
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    • 2008
  • A bridge resistance deviation-to-frequency (BRD-to-F) converter is presented for interfacing resistive sensor bridges. It consists of a linear operational transconductance amplifier (LOTA), a current-controlled oscillator (CCO). The prototype converter was simulated using commercially available discrete components. The result shows that the converter has a conversion sensitivity amounting to 16.90 kHz/${\Omega}$ and a linearity error less than ${\pm}$0.03 %.

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A Measure for Improvement in Accuracy by Performance Evaluation of a DPRMs (말뚝 변위 측정시스템의 진동 평가에 의한 정확도 향상 대책)

  • Choi Youngsam;Chung Jintai;Lee Kyeyoung;Han Changsoo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.12 s.243
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    • pp.1653-1659
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    • 2005
  • In this study, the performance of a DPRMs is evaluated and the measurement precision for the pile driving is presented. The DPRMs is a visual-measurement system for the pile rebound and the penetration movement using a high speed line-scan camera. The DPRMs generates the measurement deviation. It is caused by the strong impact for the pile driving. To reduce it, the vibration signal analysis about the pile driving is performed. As a result, it is confirmed that the tilting frequency of a camera-tripod structure corresponding to excitation frequency range of the ground is under 40Hz. Through the structure modification, the camera-tripod structure is redesigned to the model being free itself from the excitation frequency range of the ground. By the verification testing about the improvement effects, it is inspected that the tilting and measurement deviation of the redesigned DPRMs are reduced.

Frequency Dependence of High-Frequency Bottom Reflection Loss Model (주파수 종속성을 갖는 고주파 해저면 반사손실 모델)

  • 박순식;윤관섭;나정열;석동우;주진용;조진석
    • The Journal of the Acoustical Society of Korea
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    • v.23 no.5
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    • pp.362-369
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    • 2004
  • The High-frequency (30 ∼ 120 ㎑) bottom reflection loss at rough water-sediment interface is affected by the gram size distribution of the sediments. The roughness of the bottom surface is represented by "acoustical roughness. g/sub R/" The grain size of sandy sediments is g/sub R/∼O(1) and the dependence as a function of frequency. We suggest the modified bottom reflection loss model (HYBRL model , HanYang university Bottom Reflection Loss model) that include in the deviation of the reflection loss as a function of the grain size distribution and frequency dependence. And bottom reflection loss model of frequency dependence and deviation of bottom properties is verified by water tank and field experiments.

Compact Range Detection Sensor by Oscillation Frequency Deviation of an Active Antenna (능동안테나의 발진주파수 편이에 의한 소형 거리 센서)

  • Yun, Gi-Ho
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.15 no.3
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    • pp.528-535
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    • 2011
  • In this paper, a compact doppler sensor with oscillator type active antenna operating at 2.4GHz frequency band is proposed to measure the distance to a moving object. The oscillation frequency is shifted depending on approaching of the object, and a detection circuit discriminates the frequency deviation. The active antenna has been designed and simulated. The prototype fabricated has a small circular disk type of diameter 30mm and height 4.2mm. As for antenna performance, broadside radiation pattern with beamwidth of $120^{\circ}$ and oscillation frequency of 2.35GHz has been measured. Test results as a range sensor shows that signal voltage of about 240mV has been obtained for conducting plate moving 1 meter away from the sensor. And, signal voltage has been linearly increased to the ground from 5m height by free-falling the sensor.

A Study on the Load Frequency Control of 2-Area Power System using Fuzzy-Neural Network Controller (퍼지-신경망 제어기를 이용한 2지역 계통의 부하주파수제어에 관한연구)

  • Chung, Hyeng-Hwan;Kim, Sang-Hyo;Joo, Seok-Min;Lee, Jeong-Phil;Lee, Dong-Chul
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.2
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    • pp.97-106
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    • 1999
  • This paper proposes the structure and the algorithm of the Fuzzy-Neural Controller(FNNC) which is able to adapt itself to unknown plant and the change of circumstances at the Fuzzy Logic Controller(FLC) with the Neural Network. This Learning Fuzzy Logic Controller is made up of Fuzzy Logic controller in charge of a main role and Neural Network of an adaptation in variable circumstances. This construct optimal fuzzy controller applied to the 2-area load frequency control of power system, and then it would examine fitness about parameter variation of plant or variation of circumstances. And it proposes the optimal Scale factor method wsint three preformance functions( E, , U) of system dynamics of load frequency control with error back-propagation learning algorithm. Applying the controller to the model of load frequency control, it is shown that the FNNC method has better rapidity for load disturbance, reduces load frequency maximum deviation and tie line power flow deviation and minimizes reaching and settling time compared to the Optimal Fuzzy Logic Controller(OFLC) and the Optimal Control for optimzation of performance index in past control techniques.

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Circuit Models for Low Frequency Modulation Characteristics of Semiconductor Lasers (반도체 레이저의 저주파 변조특성의 회로 모델)

  • 소준호
    • Proceedings of the Optical Society of Korea Conference
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    • 1989.02a
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    • pp.214-217
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    • 1989
  • The most attractive feature of semiconductor lasers as sources for coherent optical communication system is the ability to produce frequency modulation by modulation of the bias current. The frequency deviation of semiconductor lasers under direct modulation depends on the laser structure and modulation frequency. This paper describes a circuit modeling techniques for the directly frequency modulated CSP (Channeled Substrated Planner) semiconductor laser. Predictions from this model are compared with the other published results of sinusoidal frequency modulation below than 1 GHz.

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Power Sharing Method for a Grid connected Microgrid with Multiple Distributed Generators

  • Nguyen, Khanh-Loc;Won, Dong-Jun;Ahn, Seon-Ju;Chung, Il-Yop
    • Journal of Electrical Engineering and Technology
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    • v.7 no.4
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    • pp.459-467
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    • 2012
  • In this paper, a grid connected microgrid with multiple inverter-based distributed generators (DGs) is considered. DG in FFC mode regulates the microgrid as a controllable load from the utility point of view as long as its output is within the capacity limit. The transition mode causes a change in frequency of microgrid due to the loss of power transferred between main grid and microgrid. Frequency deviation from the nominal value can exceed the limit if the loss of power is large enough. This paper presents a coordinated control method for inverter-based DGs so that the microgrid is always regulated as a constant load from the utility viewpoint during grid connected mode, and the frequency deviation in the transition mode is minimized. DGs can share the load by changing their control modes between UPC and FFC and stabilize microgrid during transition.