• 제목/요약/키워드: Gain factor

검색결과 806건 처리시간 0.029초

반도체 레이저의 변조특성에서 비선형 이득에 관한 연구 (Analysis of nonlinear gain in modulation characteristics of semiconductor lasers)

  • 엄진섭;김창봉
    • 전자공학회논문지D
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    • 제35D권2호
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    • pp.93-100
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    • 1998
  • In this paper we analyze the effect of nonlinear gain on laser modulation characteristics applying a small-signal analysis to the rate equation which includes a nonlinear gain term. Also we analyze the resonance frequency and the damping factor which determine laser modulation characteristics, define K factor which is the proportionality factor between resonance frequency and damping factor, and conclude that the decrease in K factor is due to increases in differential gain and no correlation between K factor and nonlinear gain is identified.

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Optimum Array Processing with Variable Linear Constraint

  • Chang, Byong Kun
    • Journal of information and communication convergence engineering
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    • 제12권3호
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    • pp.140-144
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    • 2014
  • A general linearly constrained adaptive array is examined in the weight vector space to illustrate the array performance with respect to the gain factor. A narrowband linear adaptive array is implemented in a coherent signal environment. It is shown that the gain factor in the general linearly constrained adaptive array has an effect on the linear constraint gain of the conventional linearly constrained adaptive array. It is observed that a variation of the gain factor of the general linearly constrained adaptive array results in a variation of the distance between the constraint plane and the origin in the translated weight vector space. Simulation results are shown to demonstrate the effect of the gain factor on the nulling performance.

Correlation Between the Optical Performance of the Reflective Polarizer and the Structure of LCD Backlight

  • Yu, Mi-Yeon;Lee, Byung-Woo;Lee, Jeong-Ho;Ko, Jae-Hyeon
    • Journal of the Optical Society of Korea
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    • 제13권2호
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    • pp.256-260
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    • 2009
  • The optical performance of the reflective polarizer was investigated over three kinds of direct-lit backlights and/or different configurations of the optical sheets. The optical gain factor achieved by using the reflective polarizer increased as the diffuse nature of the optical sheet was enhanced, because of the more efficient polarization conversion. In addition, the gain factor decreased substantially in flat-lamp backlights compared to tubular-lamp backlights, which was ascribed to the high loss factor during the polarization recycling process due to the complex structure and large area of flat lamps. All these results suggested that reducing the loss factor of the backlight is very important for efficient polarization conversion and thus high optical gain of the reflective polarizer.

가변 이득을 가지는 단상 PFC 디지털 제어기 (The Digital Controller of the Single-Phas Power Factor Correction(PFC) having the Variable Gain)

  • 정창용
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2000년도 전력전자학술대회 논문집
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    • pp.163-167
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    • 2000
  • This paper presents the digital control of single-phase power factor correction(PFC) converter which has the variable gain according to the condition of inner control loop error. Generally the gain of inner current control loop in single-stage PFC converter has a constant magnitude. This has a bad influence on the power factor because current loop doesn't operate smoothly in the condition that input voltage is low In particular a digital controller has more time delay than an analog controller and degrades This drops the phase margin of the total digital PFC system,. It causes the problem that the gain of current control loop isn't increased enough. In addition the oscillation happens in the peak value of the input voltage open loop PFC system gain changes according to ac input voltage. These aspects make the design of the digital PFC controller difficult The digital PFC controller presented in this paper has a variable gain of current control loop according to input voltage. The 1kW converter was used to verify the efficiency of the digital PFC controller.

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마이크로 셀 환경에서의 안테나 높이 이득 해석 (An Analysis of the Antenna Height Gain Factor in Microcell Environment)

  • 김병옥;하덕호
    • 한국전자파학회논문지
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    • 제8권6호
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    • pp.551-557
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    • 1997
  • 이동통신에 있어서 안테나 높이에 대한 이득은 6 dB / octave로 잘 알려져 있다. 그러나 이동통신의 전파환경은 단순하지 않고 지형지물에 따라서 변하기 때문에 안테나 높이에 대한 이득도 전파환경에 따라서 달라칠 수 있다. 이 논문은 도심지 마이크로셀 환경에서의 기지국 안테나 높이 변화에 따른 수선전력의 변화를 평탄지형과 경 사지형을 모텔로하여 이론적으로 해석한 것이다. 또한 안테나 높이 이득이 나타나기 시작하는 거리인 이득점을 사률레이션에 의해 설험적으로 구하였다.

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General Linearly Constrained Narrowband Adaptive Arrays in the Eigenvector Space

  • Chang, Byong Kun
    • Journal of information and communication convergence engineering
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    • 제15권3호
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    • pp.137-142
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    • 2017
  • A general linearly constrained narrowband adaptive array is examined in the eigenvector space. The optimum weight vector in the eigenvector space is shown to have the same performance as in the standard coordinate system, except that the input signal correlation matrix and look direction steering vector are replaced with the eigenvalue matrix and transformed steering vector. It is observed that the variation in gain factor results in the variation in the distance between the constraint plane and the origin in the translated weight vector space such that the increase in gain factor decreased the distance from the constraint plane to the origin, thus affecting the nulling performance. Simulation results showed that the general linearly constrained adaptive array performed better at an optimal gain factor compared with the conventional linearly constrained adaptive array in a coherent signal environment and the former showed similar performance as the latter in a noncoherent signal environment.

일반 선형제약 적응배열 (General linearly constrained adaptive arrays)

  • 장병건
    • 한국음향학회지
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    • 제36권3호
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    • pp.151-157
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    • 2017
  • 잡음신호제거 성능을 향상시키기 위하여 일반선형제약적응배열이 제안되었다. 잡음신호제거 성능이 배열계수 벡터공간에서 검토되었다. 제약면이 이득요소에 의하여 원점에 대하여 수직 방향으로 이동하는데 이득요소가 커지면 원점과의 거리는 감소하게 됨이 밝혀졌다. 따라서 이득요소의 변화가 계수벡터와 잡음신호 방향벡터와의 직교성의 정도에 영향을 주어서 일반선형제약적응배열의 잡음신호제거 성능이 이득요소에 의하여 향상되게 된다. 제안된 적응 배열은 최적의 이득요소 수치에서 간섭적인 신호환경에서는 기존의 선형제약적응배열에 비하여 더 나은 잡음신호제거 성능을 나타내고 비간섭적인 신호환경에서는 비슷한 잡음신호제거 성능을 나타냄이 관찰되었다.

Opposite 필터를 적용한 가변 Q 디지털 그래픽 이퀄라이저 (A Variable-Q Digital Graphic Equalizer with Opposite Filters)

  • 이용희;김인철;조국춘
    • 대한전자공학회논문지SP
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    • 제41권4호
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    • pp.131-139
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    • 2004
  • 본 논문에서는 opposite 필터를 적용한 가변 Q 디지털 그래픽 이퀄라이저를 제안한다. 그리고 제안한 이퀄라이저를 설계하는 방법을 제시한다. 본 논문에서 제안하는 가변 Q 이퀄라이저에서는 이퀄라이저의 성능을 개선하기 위해서 이득에 따라 이퀄라이저 필터의 Q-factor를 조정한다. 또한, opposite 필터의 Q-factor를 이득이 높아짐에 따라 완만하게 증가하도록 설정함으로써 opposite 필터가 대역간 간섭을 효과적으로 제거할 수 있게 한다. 실험을 통해 제안한 opposite 필터를 적용한 가변 Q 이퀄라이저는 사용자가 설정한 이득을 매우 충실하게 표현함을 보이겠다.

가변이득을 가지는 디지털제어 단상 역률보상회로 (Single-Phase Power Factor Correction(PFC) Converter Using the Variable gain)

  • 백주원;신병철;정창용;이영운;유동욱;김홍근
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.240-243
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    • 2001
  • This paper presents the digital controller using variable gain for single-phase power factor correction (PFC) converter. Generally, the gain of inner current control loop in single-stage PFC converter has a constant magnitude. This is why input current is distorted under low input voltage. In particular, a digital controller has more time delay than an analog controller which degrades characteristics of control loop. So, it causes the problem that the gain of current control loop isn't increased enough. In addition, the oscillation happens in the peak value of the input voltage open loop PFC system gain changes according to ac input voltage. These aspects make the design of the digital PFC controller difficult. In this paper, the improved digital control method for single-phase power factor converter is presented. The variable gain according to input voltage and input current help to improve current shape. The 800W converter is manufactured to verify the proposed control method.

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Dependence of the Gain Factor of the Reflective Polarizer on the Configuration of Optical Sheets

  • Lee, Byung-Woo;Yu, Mi-Yeon;Ko, Jae-Hyeon
    • Journal of Information Display
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    • 제10권1호
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    • pp.28-32
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    • 2009
  • The correlation between the optical performance of the reflective polarizer, which is a key optical component for the brightness enhancement of the liquid crystal display (LCD), and the configuration of optical sheets was investigated in a direct-lit CCFL (cold-cathode fluorescent lamp) backlight. The optical gain of the reflective polarizer, the polarization state of the light emitted from each film, and the loss factor for the polarization conversion process occurring in the lower part of the backlight were determined using a phenomenological approach for the polarization recycling process. The present study suggests that the correlation between the optical performance of the brightness enhancement films and the backlight configuration should be carefully considered in the optimization of the backlight structure.