• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.213-217
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• 2015

Microwave Photonic(MWP) filters capable of use a bandpass filter or a notch filter with large bandwidth have been proposed. 4-lines${\times}$2-bit fiber-optic delay lines with a unit time-delay difference of 50 ps were experimentally realized. By changing the time-delay difference and the coefficients of microwave-modulated optical signals, the bandpass and notch filters were implemented and characterized.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.11 s.353
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• pp.175-184
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• 2006

In this paper, we describe a 900MHz CMOS RF transceiver using an ISM band for ZigBee applications. The architecture of the designed rx front-end, which consists of a low noise amplifier, a down-mixer, a programmable gain amplifier and a band pass filter. And the tx front-end, which consists of a band pass filter, a programmable gain amplifier, an up-mixer and a drive amplifier. A low-if topology is adapted for transceiver architecture, and the total current consumption is reduced by using a low power topology. Entire transceiver is verified by means of post-layout simulation and is implemented in 0.18um RF CMOS technology. The fabricated chip demonstrate the measured results of -92dBm minimum rx input level and 0dBm maximum tx output level. Entire power consumption is 32mW(@1.8VDD). Die area is $2.3mm{\times}2.5mm$ including ESD protection diode pads.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.7
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• pp.525-536
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• 2014

In this paper, GUI program for microspeaker system simulation program was developed and verified through closed box, vent box and 6th order bandpass enclosure system. By using the pseudo loudspeaker model concept, TS parameters and rear volume of microspeaker were identified. Their suitabilities were proved by comparing test results with simulations of electrical impedance and sound pressure response curves for the three box types; closed box, vent box and 6th order bandpass box. Also, MSSP was found to be effective regardless of the microspeaker's shape, either circular or rectangular shape. MSSP can be used for the microspeaker system simulation, and can give a general prediction of such as; sound pressure level curve, electrical impedance, diaphragm velocity and displacement curve according to multiple design parameters; diaphragm mass, compliance, force factor, front and rear volume, front and rear port's diameter and length.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.949-954
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• 2012

The K-PCS and W-CDMA dual band dielectric duplexer and bandpass filters have been designed and fabricated. The dual band duplexer consists of the separate monoblock K-PCS and W-CDMA duplexers using common antenna port. The coupling capacitance and I/O impedance matching have been designed to minimize the cross interference between the bands. Isolations of crosspoint between Tx and Rx in K-PCS and W-CDMA dualband were about 47 dB and 100 dB, respectively. On the other hand, isolations of Tx and Rx in K-PCS and W-CDMA were about 66 dB and 65 dB, respectively. The difference between 47 dB and 100 dB originated from the different center frequencies in Tx and Rx of K-PCS and W-CDMA bands. The coupling capacitance of the bandwidth, I/O capacitance of I/O matching and impedance matching, and various capacitances were important role to fabricate the dielectric duplexer and bandpass filters.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3
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• pp.245-255
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• 2002

This thesis deals a method to deliver more realistic sound by cancelling the cross-talk which is inherent to the 5.1 channel speaker system. The acoustical model for cross-talk cancellation is the free field model. This model minimizes distortion of sound. I used the bark scale sound quality compensation which based on psycho-acoustic. For the surround channels, band-limited sound quality compensation is performed in the frequency domain. I also performed the sound quality assessment test on the traditional 2 channel stereo and 5.1 channel system. This test is performed in the test chamber which satisfies the ITU-R specifications. I uses the IACC (Inter-Aural Cross-Correlation) to determine the preferences of the amateur and the golden ear experts to asses the trans-aural filter. According to the result from the proposed method, I got more the 38 dB separation rates with the Dolby standard speaker array. The results on the diffusion by the subjective test with the experts shows 0.4 point increased then before.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.6
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• pp.1-8
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• 1999

Multi-carrier CDMA is a transmission scheme where data symbols are spread in the frequency domain with a spread code then transmitted using multiple carriers. It is robust against narrowband interference because of its long symbol duration. However, due to large sidebands of the rectangular window frequency response, subchannels spectrally overlap with neighboring subchannels, which leads to substantial intercarrier interference in a dispersive channel. In this paper, we consider a mult-carrier CDMA system where subchannel spectral containment is achiveved by M-band cosine modulated filter bank (CMFB). In CMFB based MC-CDMA, subchannel spectral containment is achieved using the filter bank of longer impulse response than that of conventional discrete Fourier transform (DFT) filter bank. We show that spectral containment feature of the CMFB based fading channel is analyzed using computer simulations.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.345-352
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• 2004

This paper deals a method to deliver more realistic sound by cancelling the cross-talk which is inherent to the 5.1 channel speaker system. The acoustical model for cross-talk cancellation is the free field model. This model minimizes distortion of sound. 1 used the bark scale sound quality compensation which based on psycho-acoustic. For the surround channels, band-limited sound quality compensation is performed in the frequency domain. I also performed the sound qualify assessment test on the traditional 2 channel stereo and 5.1 channel system. This test is performed in the tort chamber which satisfies the ITU-R specifications. 1 uses the IACC(Inter-Aural Cross-Correlation) to determine the preferences of the amateur and the golden ear experts to asses the trans-aural filter. According to the result from the proposed method, I got more the 38dB separation rates with the Dolby standard speaker array. The results on the diffusion by the subjective test with the experts shows 0.4∼0.5 point Increased then before.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.1
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• pp.83-90
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• 2019

LED lighting is spreading on the strength of LED lighting, and various government policies are being implemented. VLC research which is a wireless communication technology using lighting has been actively conducted, and it has been proven through many studies that a general LED light source such as a high-speed data transmitter can be used. But from now on, one of the main problems is the noise from side lights, which can be compared to the noise of radio broadcasts. So in this paper, we proposed a noise canceling model to remove the interference of ambient light by using an optical filter for a detachable VLC channel. In order to verify the proposed model, various high brightness RGB LED modules were used for comparative analysis. In addition, the applicability was verified through experiments using High Luminance LED lighting which is applied in real life.

• Proceedings of the Acoustical Society of Korea Conference
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• 1998.06e
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• pp.381-384
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• 1998

본 논문은 주행중인 자동차 환경에서 운전자의 안전성 및 편의성의 동시 확보를 위하여, 보조적인 스위치 조작없이 상시 음성의 입, 출력이 가능하도록 한다. 이때 잡음에 강인한 threshold 값을 구하기 위하여, 일정한 시간마다 기준 에너지와 영교차율(Zero Crossing Rate)을 변경하며, 밴드패스 필터(bandpass filter)를 이용하여 1차, 2차로 나누어 실시간 상태에서 자동으로, 정확하게 끝점검출(End Point Detection)을 처리한다. 기준패턴(reference pattern)은 DMS(Dynamic Multi-Section)을 사용하며, 화자의 변별력을 높이기 위하여 2개의 모델사용을 제안한다. 또한 주행중인 차량의 잡음환경에 강인하기 위하여 일반주행(80km/h 이내), 고속주행(80km/h 이상)등으로 나누며 차량의 가변잡음 크기에 따라 자동으로 선택하도록 한다. 음성의 특징 벡터와 인식 알고리즘은 PLP 13차와 One-Stage Dynamic Programming (OSDP)를 이용한다. 실험결과, 자주 사용되는 차량 편의장치 제어명령 33개에 대하여 중부, 영동 고속도로(시속 80Km/h 이상)에서 화자독립 89.75%, 화자종속 90.08%의 인식율을 구하였으며, 경부 고속도로에서는 화자독립 92.29%, 화자종속 92.42%의 인식율을 구하였다. 그리고 저속 주행중인 자동차 환경(80km/h 이내, 시멘트, 아스팔트 등의 서울시내 및 시외독립)에서는 화자독립 92.89%, 화자종속 94.44% 인식율을 구하였다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1609-1610
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• 2015

국내 철도 변전소의 부하전력은 부하인 철도차량의 부하특성에 의해 고조파와 역률이 매우 좋지 못한 실정이다. 이러한 이유에서 철도변전소에는 고조파를 보상하기위한 고조파 저감설비와 역률을 개선시키기 위한 역률보상용 콘덴서와 같은 전력품질개선설비(FACTs) 들이 설치되고 있다. 본 논문에서는 이러한 철도차량 부하의 차량별 고조파 특성을 살펴보고, 이를 효과적으로 제어할 수 있는 방법을 제안하였다. 제안된 알고리즘은 고조파저감설비의 위상제어를 통한 역률 향상을 도모하기 위한 것으로 일반적인 밴드패스 필터를 사용한 고조파 전류성분 검출에 따른 제어방식과 달리 고조파 전류에 대한 Lyapunov 안정도에 기반을 둔 제어방식을 적용하여 빠른 전류제어 동특성을 같도록 제안하였고 시뮬레이션과 실 부하 계통에 설치하여 운용함으로 그 타당성을 입증하였다.