• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.779-782
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• 2000

능동 소오나 시스템에서는 잔향음 제한 환경에서 표적 검출을 하기가 용이하지 못하다. 본 논문에서는 고정된 노치 필터로 제거할 수 없는 시 불변성의 잔향음을 효과적으로 제거할 수 있는 방법을 제안하였다. 제안된 알고리즘은 기존의 적응형 잡음 제거기가 갖고 있는 단점을 보완하기 위하여, Gram-Schmidt 직교화과정을 전처리 기법으로 사용하였다. 아울러, 제안된 잔향음 기법을 동해에서 실측한 자료에 적용함으로써 그 성능을 검증하였다.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1264-1267
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• 1987

In this study, a new implementation of an adaptive noise filter is proposed to eliminate timevarying 60Hz noise and its harmonics in ECG signal. The new technique was applied to the ECG and it was found in the experiment that it showed much better characteristics than conventional method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.195-196
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• 2006

• Journal of Satellite, Information and Communications
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• v.12 no.3
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• pp.63-68
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• 2017

SAR(Synthetic Aperture Radar) uses electromagnetic signals to acquire ground information and has been used for wide coverage reconnaissance missions regardless of weather conditions. However SAR is known to be vulnerable to interference signals by other communication devices or radar instruments and may suffer from undesirable performance degradations and image quality. In this paper, a modified Eigen-subspace based filter is proposed that can be easily applied to SAR images affected by interference signals. The method of constructing Eigen-subspace based filter is briefly described and various simulations are performed to show the performance of the interference mitigation process. The suppression filter is applied to a ALOS PALSAR raw data affected by interfering signals in order to verify its superiority over the Notch filter.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.456-459
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• 1993

A new filter-bank is proposed in order to track center frequency of narrow bard signal. The filter-bark proposed here has a laster and a slave filter bark. The two barks are connected in series-parallel. The master filter bank which is made of traditional filter bank detects the center frequency roughly. And the performance for tracking center frequency is greatly improved by the slave filter bank which is based or energy-difference estimator. Computer simulations show that it achieves a good tracking accuracy.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.307-314
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• 2021

Even though the LCL filters have superior harmonic attenuation ability to L filters, stability has always been an issue. The system could be unstable because of the resonance phenomenon, especially when digital controller is used. Adding a notch filter to the compensator is one approach to solve the problem. Resonance phenomenon can be inhibited by aligning notch frequency to system resonance frequency. However, resonance frequency variation can be obtained because the actual system has a nonstationary characteristic. Therefore, the system could be unstable, where the system parameters are changed when the conventional notch filter is used. An adaptive digital notch filter that stabilizes the system even system parameters are changed. Simulation and experiment results are provided to verify the validity of the proposed adaptive filter.

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.106-112
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• 2012

As a fuel cell converts the chemical energy of the fuel cell into electrical energy by electrochemical reaction, the fuel cell system is uniquely integrated technique including fuel processor, fuel cell stack, power conditioning system. The residential fuel cell-PCS(Power Conditioning System) needs to convert efficiently the DC current produced by the fuel cell into AC current using single-phase DC-AC inverter. A single-phase DC-AC inverter has naturally low frequency ripple which is twice frequency of the output current. This low frequency(120Hz) ripple reduces the efficiency of the fuel cell. This paper presents notch filter with IP voltage controller to reject specific 120Hz current ripple in single-phase inverter. The notch filter is designed that suppress just only specific frequency component and no phase delay. Finally, the proposed notch filter design method has been verified with computer simulation and experimentation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.11
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• pp.77-83
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• 2009

In this paper, a selective feedback low-noise amplifier (LNA) has been realized in a $0.18{\mu}m$ CMOS technology to cover a number of wireless multi-standards. By exploiting notch filter, the SF-LNA demonstrates the measured results of the power gain (S21) of 11.5~13dB and the broadband input/output impedance matching of less than -10dB within the frequency bands of 820~960MHz and 1.5~2.5GHz, respectively. The chip dissipates 15mW from a single 1.8V supply, and occupies the area of $1.17\times1.0mm^2$.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.325-330
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• 2012

A single-phase PVPCS(photovoltaic power conditioning system) that contains a single phase dc-ac inverter tends to draw an ac ripple current at twice the out frequency. Such a ripple current may shorten passive elements life span and worsen output current THD. As a result, it may reduce the efficiency of the whole PVPCS system. In this paper, the ripple current propagation is analyzed, and two methods to reduce the ripple current are proposed. Firslyt, this paper presents notch filter with IP voltage controller to reject specific current ripple in single-phase PVPCS. The notch filter can be designed that suppress just only specific frequency component and no phase delay. The proposed notch filter can suppress output command signal in the ripple bandwidth for reducing output current THD. Secondly, for reducing specific current ripple, the other method is feed-forward compensation to incorporate a current control loop in the dc-dc converter. The proposed notch filter and feed-forward compensation method have been verified with computer simulation and simulation results obtained demonstrate the validity of the proposed control scheme.

• Korean Journal of Optics and Photonics
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• v.19 no.4
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• pp.315-319
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• 2008

We investigate theoretically the power consumption of a notch filter using a thermo-optic long-period grating, which is induced by a heater array consisting of periodic heaters and pads made of metal thin-film. Since the power consumed by the heater array is converted to joule heat that generates the thermo-optic long-period grating, the characteristics of the notch filter are dynamically controlled by adjusting it. The power necessary for appropriate coupling efficiency depends on the parameters of the heater array, which are the width and length of a heater, pad width, and the thickness of the thin-film. We explain an approximate method of analyzing the influence of the parameters on the consumed power. Using the analysis method, we simulate the change of the power depending on the parameters. From the simulation, we suggest a few guidelines on the parameters required to reduce the power.