• Journal of Power Electronics
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• v.15 no.6
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• pp.1421-1428
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• 2015

The efficiency and reliability of the dual-buck inverter (DBI) were greatly improved by eliminating the shoot-through problem and optimally designing the freewheeling diode. The traditional DBI suffers from large harmonic components with low output voltage and large capacity output filter inductor. To overcome the aforementioned disadvantages, a modified DBI (MBDI) was proposed by adopting a quasi-resonant link and pulse density modulation (PDM). This paper first introduces the working principle of the MBDI and PDM, and then the selection principle of system parameters is presented. Finally, a mathematical model of the MBDIis built, and an experiment prototype is set up. Simulation and experimental results verify the correctness of the theoretical analysis and the feasibility of the scheme.

• Journal of Industrial Technology
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• v.31 no.B
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• pp.67-73
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• 2011

Ceramic metal halide lamps have been widely used due to long lifetime, high luminous efficiency and good colour rendering. In this paper, we developed dimming control system of electronic ballast for 70W ceramic metal halide lamp by using 1-10V interface. The proposed electronic ballast is consists of EMI filter, Full-wave rectifier, Active PFC, DBI(Dual Buck Inverter), Igniter and control circuit.It enables to supply both low-frequency rectangular wave voltage and current to the lamp by using DBI(Dual Bcuk Inverter) structure. By using 1-10V interface, the system that able to dimming the lamp is demonstrated by P-spice simulation and experimental results.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.435-436
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• 2008

This paper presents a dual band frequency synthesizer for GSM and Wideband CDMA which is designed in a standard 0.13um CMOS 1P6M process. The shared components include phase frequency detector (PFD), charge pump (CP), loop filter, integer frequency divider(128/129 DMP, 4bit PC, 3bit SC) and Low noise Ring-VCO. A high-speed low power dual modulus prescaler is proposed to operate up to 2.1GHz at 3.3V supply voltage with 2mW power consumption by simulation. The simulated phase noise of VCO is -101dBc/Hz at 200kHz offset frequency from 1.9GHz.

• ETRI Journal
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• v.39 no.1
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• pp.69-75
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• 2017

This study presents a dual-band 3D frequency selective surface that provides a large degree of freedom in frequency and bandwidth adjustability. The proposed structure is evaluated in terms of its structural parameters, and prototypes are fabricated. The radius of the copper rings and the height of the cylinders are considered, and are shown through full-wave electromagnetic simulations to have a significant effect on the frequency characteristics of the frequency selective surface. The measurement results of the fabricated samples are compared with the simulation results, and a satisfactory agreement is obtained.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.1-7
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• 2010

Ceramic metal halide lamps have been widely used due to long lifetime, high luminous efficiency and good colour rendering. 35[W] ceramic metal halide lamps has very different characteristics between ignition state and steady state. The developed electronic ballast is satisfied to both ignition state and steady state characteristics by using a micro-controller. The proposed electronic ballast is consists of EMI filter, Full-wave rectifier, Active PFC, DBI(Dual Buck Inverter), Igniter and control circuit. It enables to supply both low-frequency rectangular wave voltage and current to the lamp by using DBI(Dual Bcuk Inverter) structure.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2480-2482
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• 1998

In this paper, the implementation of dual rate ADPCM using G.723 16Kbps and 40Kbps speech codec algorithm is handled. For small signals, the low rate 16Kbps coding algorithm shows the same SNR as the high rate 40Kbps coding algorithm, while the low rate 16Kbps coding algorithm shows the lower SNR than the high rate 40Kbps coding algorithm for large signal. To obtain the good trade-off between the data rate and synthesized speech quality, we applied low rate 16Kbps for the small signal and high rate 40Kbps for the large signal. Various threshold values determining the rate are tested for good trade off data rate and speech quality. Also the low pass filter effect of speech input and output devices is simulated at several cut-off frequencies. To simulation result shows the good speech quality at a low rate comparing with 16Kbps & 40Kbps.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.2
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• pp.107-112
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• 2002

There are many combination with the porosity of tipping paper and plug wrap for a design of ventilation rate of cigarette. This study was carried out to determine the effect of a design of permeability of tipping paper and inner or outer of plug wrap on the ventilation rate of cigarette with constant pressure drop in column part and filter part. Our results indicated that the higher the plugwrap porosity, the higher the ventilation rate and the less variable of cigarette in case of mono filter. But, in case of duel filter, the ventilation rate of cigarette was depended on the manufacturing method of filter plug, even though using the same porous plug wrap on inner and outer of filter. We also found that the porosity of outer plug wrap was more effect on the ventilation rate than the porosity of inner plug wrap. As the high porosity of inner plug wrap compared with the porosity of outer plug wrap, the less variable of ventilation rate of cigarette in any combination of the porosity of plug wrap. When we used the higher porous outer plug wrap than inner plug wrap, the ventilation rate of cigarette was high. Also, the higher the inner plug wrap porosity, the less variable of ventilation rate of cigarette.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.203-204
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• 2007

• 전기의세계
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• v.34 no.1
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• pp.5-12
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• 1985

대전력.고주파화가 가능한 유도기구동방식을 소개하였다. 앞으로의 Dual-inverter에 의한 구동방식은 Fly-wheel에 의한 전절의 회생에너지 저장에서의 응용에 적합하다고 생각되며, 고주파 Cycloconverter는 입력전류의 력율및 파형의 제어가 가능함으로, 무효전력제어, Fly-wheel에 의한 에너지 저장, 장해전력 보상용 Active filter 등에 응용이 가능하리라 믿는다.

• Journal of IKEEE
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• v.10 no.2 s.19
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• pp.109-115
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• 2006

In this paper, High order derivative Gaussian pulse generator for DS-UWB communication satisfying the regulation of FCC was proposed and fabricated. In order to transform rectangular signal of 100Mbps to a Gaussian pulse, the fabricated Gaussian pulse generator consists of only two SRD. The output pulse had the widths of 330 psec and amplitudes of 920 mV. In addition, the designed and fabricated dual bandpass filter shows high order derivate characteristics by using micro-strip line and parallel stub to remove WLAN band. We generated the 13th Gaussian pulse restricted frequency spectrum of WLAN band more than -25dB. The pulse had pulse width of 1 nsec and amplitude of 25 mV.