• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.98-107
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• 2016

An analytical comparison of a synthetic memristor emulator and a M-R mutator-based memristor emulator has been performed. Memristor is an electrical element with the characteristic of variable resistance. It is called the fourth fundamental electrical element following resistor, capacitor, and inductor. Memristor emulator is a circuit which implements the feature of variable resistance via the composition of various electrical devices. It is an essential circuit to study memristor characteristics during the time before it is commercially available. There are two representative memristor emulators depending upon their implementation methods. One is a memristor emulator which is synthesized via combining various electrical devices and the other one is M-R mutator-based memristor emulator implemented by extracting resistance from a nonlinear device. In this paper, implementation methods of these two memristor emulators are studied and their differences are investigated by analysing their characteristics.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.1
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• pp.50-54
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• 1983

Contact resistance variation which may be called sliding noise in carbon film variable resistors whose resistance elements consists of linear resistivity distribution were measured with several kinds of sliders and were analyzed to reduce the contact resistance variation. About the measuring method, the standard method of measuring contact resistance variation specified by the variable Resistance Components Institute was adupted. By analyzing the experimental results, it has been shown that the primary cause of contact resistance variation is due to current constriction and small discharge sparks in the resistance film in the area close to the slide contact. Moreover, it has been found that the sliding noise would be reduced by increasing the number of contact points, sliding speed, and pressure, and by using some kinds of insulation oil on the contacting surface. High contact resistance variation is likely to occur in the area of high resistance variation in a logrithmic resistance taper.

• Journal of IKEEE
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• v.7 no.1 s.12
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• pp.43-55
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• 2003

A degenerated differential pair has been widely used as a standard topology for digitally programmable CMOS VGAs. A variable degeneration resistor has been implemented using a resistor string or R-2R ladder with MOSFET switches. However, in the VGAs using these conventional methods, low-voltage and high-speed operation is very hard to achieve due to the dc voltage drop over the degeneration resistor. To overcome the problem a new variable degeneration resistor is proposed where the dc voltage drop is almost removed. The proposed gain control scheme makes it easy to implement a low-voltage and high-speed VGA. This paper describes the problems existed in conventional methods, the principle and advantages of the proposed scheme, and their performance comparison in detail. A CMOS VGA cell is designed using the proposed degeneration resistor. The 3dB bandwidths are greater than 650㎒ and the gain errors are less than 0.3dB in a gain control range from -12dB to +12dB in 6dB steps. It consumes 3.1㎃ from a 2.5V supply voltage.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.4
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• pp.275-281
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• 2003

A new neural oscillator has been designed and fabricated in an 0.5 ${\mu}{\textrm}{m}$ double poly CMOS technology. The proposed neural oscillator consists of a nonlinear variable resistor with negative resistance as well as simple transconductors and capacitors. The variable negative resistor which is used as a input stage of the oscillator consists of a positive feedback transconductors and a bump circuit with Gaussian-like I-V curve. The proposed neural oscillator has designed in integrated circuit with SPICE simulations. Simulations of a network of 4 oscillators which are connected with excitatory and inhibitory synapses demonstrate cooperative computation. Measurements of the fabricated oscillator chip with a $\pm$ 2.5 V power supply is shown and compared with the simulated results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.445-453
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• 2000

In this paper, the method of designing an active inductor for MMIC is proposed. The proposed tunable active inductor is composed of a cascade FET with feedback capacitors and resistors. Because of a very low series resistance in the proposed inductor, a very high Q factor can be obtained. Also it has an excellent characteristics suitable for high frequency band. The inductance value can be changed by controlling feedback capacitors, resistors and a bias voltage respectively. When the feedback resistor and parallel resistor within circuits are varied, the inductance value is changed from 0.2 nH to 1.7 nH in the range 1 to 15 GHz. Also we designed bandpass filter using the proposed active inductor and it shows the insertion loss of 0.4 dB and return loss, 20 dB.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.6046-6051
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• 2012

In this paper, we designed a Chua's chaotic circuit using transcondcutor based nonlinear resistor for secure communication applications. Proposed chaotic circuit consist of passive devices such as L and C, a MOS based variable resistor and a transcondcutor based Chua's diode. From SPICE simulation results, the proposed circuit showed variable chaotic dynamics through time waveforms, frequency analysis and phase plots.

• Journal of Ocean Engineering and Technology
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• v.11 no.4
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• pp.197-204
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• 1997

최근 유도전동기를 이용한 가변속 구동시스템의 수요가 자동화 및 에너지의 효율적 이용 측면에서 육상 산업체는 물론, 선박 및 해양플랜트에도 확산되고 있다. 유도전동기의 토크 고속제어법은 가변속 구동시스템의 고성능화를 위한 필수과제로서, 제어법 적용시 2차저항의 동정문제가 대단히 중요하다. 본 논문에서는 유도전동기의 토크 고속 응답제어계에 있어서 고정도의 토크응답을 실현하기 위한 2차저항 동정법을 제안한다. 제안된 방법은 모터의 회로방정식으로부터 유도되며, 모터의 인가전압과 1차전류 정보로부터 간단히 구현된다. 제안된 방안의 타당성을 검증하기 위하여 펄스폭변조방식의 전압형 인버터를 상정한 수치 시뮬레이션을 수행하며 그 결과를 통하여 제안방식의 유용성을 입증한다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.9
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• pp.673-684
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• 2003

A degenerated differential pair has been widely used as a standard topology for digitally programmable CMOS VGAs. A variable degeneration resistor has been implemented using a resistor string or R-2R ladder with MOSFET switches. However, in the VGAs using these conventional methods, low-voltage and high-speed operation is very hard to achieve due to the dc voltage drop over the degeneration resistor. To overcome this problem a new variable degeneration resistor is proposed where the dc voltage drop is almost removed. Using the proposed gain control scheme, a low-voltage and high-speed CMOS VGA is designed. HSPICE simulation results using a 0.25${\mu}{\textrm}{m}$ CMOS process parameters show that the designed VGA provides a 3dB bandwidth of 360MHz and a 80dB gain control range in 2dB step. Gain errors are less than 0.4dB at 200MHz and less than l.4dB at 300MHz. The designed circuit consumes 10.8mA from a 2.5V supply and its die area is 1190${\mu}{\textrm}{m}$${\times}$360${\mu}{\textrm}{m}$.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.4
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• pp.273-278
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• 2016

In this paper, chaotic circuit of the Lorentz system using multipliers, operational amplifiers, capacitor, fixed resistor and variable resistor for control has been designed in a electronic circuit. Through PSPICE program, electrical characteristics such as time waveforms, frequency spectra and phase attractors analyzed. And in the special area ($10{\sim}100k{\Omega}$) of the $500k{\Omega}$ control variable resistor, the circuit showed chaotic dynamics. Also, we implemented the circuit in a electronic hardware system with discrete elements. Measured results of the circuit coincided with simulated data.

• Journal of Korean Electronics
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• v.3 no.9
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• pp.95-100
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• 1983