• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.714-723
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• 2003

An effective technique to increase the signal swing and reduce noise is to use fully-differential -circuits. However, design of a common-mode feedback (CMFB) circuit that stabilizes the common-mode output level is essential. In this paper, a general description is given to fully-differential amplifiers with their CMFB loops, then a new error amplifier that is just composed of transistors and stabilizes the DC output level is proposed. We designed a simple and efficient bias circuit that allows the stability and maximum input swing. Simulation result shows the enhanced phase margin and increased differential-mode input swing with a proposed error amplifier.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.12
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• pp.963-968
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• 2018

In this paper, a compact common mode filter using passive elements is designed and fabricated. To design a common mode filter with required frequency response, the equivalent circuits of the common mode filter in differential mode and common mode were analyzed. Compared with the former filter using a ${\lambda}/4$ resonator, the size of the proposed structure was reduced by 60 %. The fabricated common mode filter has a maximum differential mode insertion loss of 1.2 dB and a minimum common mode absorption efficiency of 78.2% in the CMA - bandwidth of 27.5 %.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.12
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• pp.964-973
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• 2017

In this paper, we analyze the effects of parasitic components of common-mode choke on the common mode and differential mode in a wide band, and we propose a simple method for high-frequency modeling. Common mode and differential mode 2-port networks were configured and the S-parameters in each mode were measured using a network analyzer. Equivalent circuit elements were extracted from the measured results to model a high-frequency equivalent circuit, and the validity was verified by comparing the measured S-parameters with the simulation results.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.8
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• pp.867-880
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• 1992

In this paper, a circuit design techniques for Improving the voltage gain of the GaAs MESFET single amplifier is presented. Also, various types of existing current mirror and proposed current mirror of new configuration are compared. To obtain the high differential mode gain and low common mode gain, bootstrap gain enhancement technique Is used and common mode feedback Is employed In the design of differential amplifier. The simulation results show that designed differential amplifier has differential gain of 57.66dB, unity gain frequency of 23.25GHz. Also, differential amplifier using common mode feedback with alternative negative current mirror has CMRR of 83.S8dB, stew rate of 3500 V /\ulcorners.

• Journal of Industrial Technology
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• v.18
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• pp.439-442
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• 1998

In this paper, we firstly suggested C&D (Common mode and Differential mode) model for the representation of a stereophonic signal. Then a measure of stereophonic channel separability is defined as the ratio of differential mode energy to total energy in frequency domain. After that, a new channel separability enhancement scheme is proposed by the control of common mode rejection. Finally, some experimental results are presented in order to verify our scheme.

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.196-201
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• 2013

In this paper, a dual-mode balanced filter with symmetric coupled composite right/left-handed transmission line is introduced. Unlike the other symmetric structure, this configuration has the ability to operate under both common- and differential-mode excitation. These properties are achievable through providing physical short circuit by means of ground vias at the center of each unit-cell along the symmetry plane of the structure. Because the CRLH unit-cells are operated under both common- and differential-mode excitation, we implemented a balanced filter using these properties. To validity these features, a five-cell four port coupled CRLH-TL is simulated, fabricated and measured and the obtained performances agree with the simulation results under both common- and differential-mode excitation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1977-1978
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• 2008

In this paper, we compare performance of common-mode rejection between a differential and a non-differential amplifier system with two electrodes. A differential amplifier system is constant for common-mode rejection ratio(CMRR) on the frequency domain. But a non-differential amplifier's CMRR is determined by $Z_{FB}/Z_e$ ($Z_{FB}$ ; feedback impedance, $Z_e$; electrode impedance). There is trade-off between a non-differential amplifier's CMRR and its differential input impedance. And a non-differential amplifier system has some advantages for a bio-potential measurement with two electrodes because a designer can control the impedance between the body and system's common.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.571-577
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• 2011

This paper presents a novel balanced filter design based on a metamaterial structure applicable to differential-mode excitation. The metamaterial structure is based on a unit-cell which under a differential-mode excitation behaves like composite right/left-handed(CRLH) metamaterial with filter characteristics. In contrast, the metamaterial unit-cell is below cut-off under a common-mode excitation. Experimental results are used to verify the proposed metamaterial's differential-mode characteristics. The metamaterial is fabricated with a balanced filter design resulting in an operating frequency range of 960~1000 MHz with a insertion loss of 4.1 dB.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1652-1653
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• 2011

This paper builds a printed circuit board to calculate the radiated emissions due to the common-mode and differential-mode currents. The calculated results agree with the measured values. Based on the calculated values, it is shown clearly that the common-mode radiations are the dominator of the radiated emissions from the device. The radiated emissions due to the common-mode currents can easily dominate the radiated emissions from the printed circuit board.

• ETRI Journal
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• v.35 no.5
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• pp.827-837
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• 2013

In this paper, we present wideband common-mode (CM) noise suppression using a vertical stepped impedance electromagnetic bandgap (VSI-EBG) structure for high-speed differential signals in multilayer printed circuit boards. This technique is an original design that enables us to apply the VSI-EBG structure to differential signals without sacrificing the differential characteristics. In addition, the analytical dispersion equations for the bandgap prediction of the CM propagation in the VSIEBG structure are extracted, and the closed-form expressions for the bandgap cutoff frequencies are derived. Based on the dispersion equations, the effects of the impedance ratio, the EBG patch length, and via inductances on the bandgap of the VSI-EBG structure for differential signals are thoroughly examined. The proposed dispersion equations are verified through agreement with the full-wave simulation results. It is experimentally demonstrated that the proposed VSI-EBG structure for differential signaling suppresses the CM noise in the wideband frequency range without degrading the differential characteristics.