• Title/Summary/Keyword: 위상각 안정도

Search Result 91, Processing Time 0.026 seconds

Small-size PLL with time constant comparator (시정수 비교기를 이용한 작은 크기의 위상고정루프)

  • Ko, Gi-Yeong;Choi, Young-Shig
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.21 no.11
    • /
    • pp.2009-2014
    • /
    • 2017
  • A novel structure of phase locked loop (PLL) with a time constant comparator and a current compensator has been proposed. The proposed PLL uses small capacitors which are impossible for stable operation in a conventional PLL. It is small enough to be integrated into a single chip. The time constant comparator detects the loop filter output voltage variations using signals which are passed through small and large RC time constants. The signal from the large RC time constant node is the average of the loop filter output voltage. The output voltage of another node is approximately equal to the present loop filter voltage. The output of the time constant comparator controls a current compensator and charge/discharge small size loop filter capacitors. It makes the proposed PLL operate stably. It has been simulated and proved by HSPICE in a CMOS $0.18{\mu}m$ 1.8V process.

Design and Performance Analysis of the Digital Phase-Locked Loop For Frequency Hopping Spread Spectrum system (주파수도약 대역확산시스템을 위한 디지털 위상고정루프의 설계 및 성능분석)

  • Kim, Seong-Cheol
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.14 no.5
    • /
    • pp.1103-1108
    • /
    • 2010
  • In this paper, Frequency Synthesizer which is widely used for FH-SS system is proposed and the experimental results are analyzed. The performance of the DPLL(Digital Phase-Locked-Loop), which is the main part of the Synthesizer is analyzed by the computer program. Using Maxplus-II tool provided by altera. co., ltd, each part of the DPLL is designed and all of them is integrated into EPM7064SLC44-10 chip. And the simulation results are compared with the characteristics of the implemented circuits for analysis. And the experiential results show that the N value of the loop filter is toggled to adjacent N value, which result in phase jitter of the output. It can be resolved by increasing DCO(Digital Controlled oscillator) clock rate.

Effect of varying the coupling strength and section length on the self-pulsation characteristics of multisection index-coupled DFB lasers (다중 전극 Index-Coupled DFB 레이저에서 결합 세기 및 각 영역의 길이가 Self-Pulsation 동작 특성에 미치는 영향)

  • Kim, Sang-Taek;Kim, Tae-Young;Ji, Sung-Keun;Kim, Boo-Gyoun
    • Korean Journal of Optics and Photonics
    • /
    • v.16 no.1
    • /
    • pp.85-98
    • /
    • 2005
  • As the number of compound cavity modes within the stopband of DFB sections decreases, the frequency of mode hopping decreases for the variation of $\Delta$λ$_{B}$, which represents the difference between the Bragg wavelengths of two DFB sections, so that the number of abrupt changes of pulsation frequencies decreases. In addition, the pulsation frequency varies continuously for the variation of the phase in a phase tuning section for a fixed $\Delta$λ$_{B}$. The number of compound cavity modes within the stopband decreases as the length of DFB sections increases and the length of a phase tuning section decreases. Thus stable self-pulsation operations for the variation of $\Delta$λ$_{B}$ and the phase in a phase tuning section could be obtained by proper selection of the coupling strength and the length of each section.ction.

Acceleration Sensor Using Optical Fibers and Film Gratings (광섬유와 필름격자를 이용한 가속도 센서)

  • Lee, Youn-Jea;Jo, Jae-Heung;Kwon, Il-Bum;Seo, Dae-Cheol;Lee, Nam-Kwon
    • Korean Journal of Optics and Photonics
    • /
    • v.19 no.3
    • /
    • pp.175-181
    • /
    • 2008
  • We develop a fiber optic acceleration sensor with LED, PD, POF, and a cantilever beam, having film grating at the edge of the beam. Light is transmitted from LED to PD through the film grating. When the cantilever beam moves by external vibration, output light is modulated as sinusoidal signals. The characteristics of output signals are dominated by the spacing of the film grating and also by the size and the elasticity of the beam. Two output signals, having constant initial phase difference, are obtained by two gratings with 90 degree phase difference. Those two signals are used to determine phase angle, which is proportional to the displacement of the beam. Finally, the acceleration is determined from conversion equation between displacement and acceleration. This sensor is designed for monitoring the vibration of large and complex building in the low frequency range of below 7 Hz, and is particularly suitable to measure acceleration in electromagnetic environments.

An Investigation of Con01 Threshold of Vehicle Stability Control System (제어시점에 따른 차량 안정성 제어 시스템의 제어 경향)

  • Chung, Tae-Young;Yi, Kyong-Su
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.13 no.5
    • /
    • pp.195-201
    • /
    • 2005
  • In conventional Vehicle Stability Control (VSC) System, a control threshold is designed by average driver characteristics. Despite the stabilizing effort, VSC causes redundancy to an expert driver. An advanced VSC which has flexibility on its control property is proposed in this study. By using lateral velocity estimator, a control threshold is determined on side slip angle and angular velocity phase plane. Vehicle planar motion model based sliding controller is modified with respect to various control thresholds. The performance of the proposed VSC algorithm has been investigated by human-in-the-loop simulation using a vehicle simulator. The simulation results show that the control threshold has to be determined with respect to the driver steering characteristics. A VSC with variable control thresholds would provide an improvement compared to a VSC with a constant threshold.

A Utility Interactive System Control Using PV Generation (태양광 발전을 이용한 계통연계 시스템 제어)

  • Cho, Moon-Taek;Lee, Chung-Sik;Lee, Se-Hun;Hwang, Lak-Hun;Kim, Young-Soo;Na, Seung-Kwon;Song, Ho-Bin
    • Proceedings of the KIEE Conference
    • /
    • 2007.07a
    • /
    • pp.1224-1226
    • /
    • 2007
  • 전압형 인버터에 의해 제어되며 인버터의 스위칭 게이트 신호 발생은 전압변조가 필요하다. 전압변조는 삼각파 비교 PWM, 공간전압벡터(Space voltage Vector) PWM기법 등으로 실현되고 있으나, SVPWM은 타 방식에 비해 고조파의 왜형률을 감소시키고, 디지털 구현이 용이하며 선형제어 영역을 증가시킬 수 있는 장점이 있다. 따라서 본 논문에서는 먼저 SVPWM의 스위칭 이론 및 각 섹터에 따른 방향에 대해 설명하였고, 태양광발전 시스템을 3상 PWM전압형 인버터로 구성하였고 안정된 변조를 위해서 동기신호와 제어신호를 위해 모토로라사의 56F8323 마이크로프로세서에 의해서 처리하였다. 또한 시스템의 출력전압과 전류의 파형은 전원전압과 출력전류가 위상이 일치되어 단위 역률로 안정된 전력을 공급할 수 있도록 제어하였다.

  • PDF

Modeling of Force Components Acting on Quay Walls During Earthquakes (지진시 중력식 안벽에 작용하는 하중성분의 모델링)

  • 김성렬;권오순;김명모
    • Journal of the Korean Geotechnical Society
    • /
    • v.19 no.2
    • /
    • pp.107-121
    • /
    • 2003
  • When the seismic stability of quay walls is analyzed, the magnitudes of force components acting on quay walls during earthquakes and the phase relations among these force components must be properly evaluated. In general, force components include inertia force of the quay wall, lateral earth force, and water force. The magnitude and the phase relation of each force component vary according to the magnitude of the excess pore pressures developed in backfill soils of the quay wall. The dynamic thrust mobilized at the contact surface between the backfill soil and the wall develops as a result of the interactions among these force components. We propose a simple model to evaluate the magnitude and phase variation of the dynamic thrust on the back of the wall in terms of the excess pore pressure. The proposed model can predict the dynamic thrust by summing the magnitudes of farce components calculated from design equations for seismic pressures on the wall. The proposed model was verified by comparing its results with the results from a series of shaking table tests.

Effect of the Cross Magnetizatin Saturated Generators on the Analysis of Steady State Stability (정태안정도 해석에 미치는 발전기 교차자화 포화특성의 영향)

  • 김덕영
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.12 no.2
    • /
    • pp.115-120
    • /
    • 1998
  • This paper presents a modeling of a synchronous machine infinite bus system of which not only seperated saturation effect but also cross magnetization effect of the saturated generator is included for the more precise analysis of the system. In the process of reforming the flux linkage equations of the state equations which have generator saturation effects, the d-axis coordinated system of a generator is fixed that the d-axis proceeds the q-axis in $90^{\circ}$ to accord with the generally accepted generator model used before. The simulation results show that cross magnetization has a very important effect to the more precise eigenvalue analysis of steady state stability.bility.

  • PDF

Proposal of Rotating Stability Assessment Formula for an Interlocking Caisson Breakwater Subjected to Wave Forces (파랑하중에 대한 인터로킹 케이슨 방파제의 회전 안정성 평가식 제안)

  • Park, Woo-Sun;Won, Deokhee;Seo, Jihye;Lee, Byeong Wook
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.32 no.1
    • /
    • pp.11-16
    • /
    • 2020
  • The rotational stability of an interlocking caisson breakwater was studied. Using the analytical solution for the linear wave incident to the infinite breakwater, the phase difference effect of wave pressures in the direction of the breakwater baseline is considered, and Goda's wave pressure formula in the design code is adopted to consider the nonlinearity of the design wave. The rotational safety factor of the breakwater was defined as the ratio of the rotational frictional resistance moment due to caisson's own weight and the acting rotational moment due to the horizontal and vertical wave forces. An analytical solution for the rotational center point location and the minimum safety factor is presented. Stability assessment formula were proposed to be applicable to all design wave conditions used in current port and harbor structure design such as regular waves, irregular waves and multi-directional irregular waves.

Improvement of ADU(Antenna Distribution Unit) for RF signal Stability of Glide Path (활공각제공시설(Glide Path) 신호안정화를 위한 ADU(Antenna Distribution Unit) 개선)

  • Lee, Chang-Woo;Lee, Seung-Tae
    • Journal of Advanced Navigation Technology
    • /
    • v.15 no.6
    • /
    • pp.994-999
    • /
    • 2011
  • This paper explains how existing electrical ADU(Antenna Distribution Unit) has been improved into a mechanical ADU. Generally the mechanical ADU has stabilized Glide Path which provides a RF signal to the aircraft for safe landing and it has solved the issue of phase shift and power distribution ratio change which can be occurred during long-term use. Besides it has been certified by Flight check and operating several airports in oversea as well as in korea.