• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.197-199
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• 2017

This paper presents a jitter characteristic improved phase locked loop (PLL) with an RC time constant circuit. In the RC time constant circuit, LPF's voltage is inputted to a comparator through small and large RC time constant circuits. The negative feedback loop reduces the variation of loop filter output voltage resulting in jitter characteristic improvement.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.2
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• pp.133-138
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• 2017

This paper presents a jitter characteristic improved phase locked loop (PLL) with an RC time constant circuit. In the RC time constant circuit, LPF's voltage is inputted to a comparator through small and large RC time constant circuits. The signal through a small RC time constant circuit has almost same loop filter output voltage. The signal through a large RC time constant circuit has the average value of loop filter output voltage and does as a role of reference voltage to the comparator. The output of the comparator controls the sub-charge pump which provide a current to LPF. When the loop filter output voltage increases, the sub-charge pump discharges the loop filter and decreases loop filter output voltage. When the loop filter output voltage decreases, the sub-charge pump charges the loop filter and increases loop filter output voltage. The negative feedback loop reduces the variation of loop filter output voltage resulting in jitter characteristic improvement.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.295-303
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• 2004

Previously it has been shown that the all pole systems resulting good time responses can be characterized by so called K-polynomial. The polynomial is defined in terms of the principal characteristic ratio $\alpha_1$ and the generalized time constant $\tau$ . In this paper, Part II presents several sensitivity analyses of such systems with respect to $\alpha_1$ and $\tau$ changes. We first deal with the root sensitivity to the perturbation of $\alpha_1$ . By way of determining the unnormalized function sensitivity, both time response sensitivity and frequency response sensitivity are derived. Finally, the root sensitivity relative to $\tau$ change is also analyzed. These results provide some useful insight and background theory when we select of and l to compose a reference model of which denominator is a K-polynomial, which is illustrated by examples.

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.122-129
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• 2001

A characterization procedure for analyzing symmetric coupled MIS(Metal-Insulator-Semiconductor) transmission line is used the same procedure as a general single layer symmetric coupled line with perfect dielectric substrate from the extraction of the characteristic impedance and propagation constant for even- and odd-mode. In this paper, an analysis for a new substrate shielding symmetric coupled MIS structure consisting of grounded crossbar at the interface between Si and SiO2 layer using the Finite- Difference Time-Domain(FDTD) method is presented. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded crossbar lines over time-domain signal has been examined. Symmetric coupled MIS transmission line parameters for even- and odd-mode are investigated as the functions of frequency, and the extracted distributed frequency- dependent transmission line parameters and corresponding equivalent circuit parameters as well as quality factor for the new MIS crossbar embedded structure are also presented. It is shown that the quality factor of the symmetric coupled transmission line can be improved without significant change in the characteristic impedance and effective dielectric constant.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.3
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• pp.398-405
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• 2003

A fast response analyzer for measuring carbon dioxide concentration has been developed for transient characteristic and researches tested on internal combustion engine. The analyzer uses the well known NDIR(Non-Dispersive Infrared) method with miniaturized detection system, giving a time constant of approximately 30 microsecond, and sampling module consists of capillary tube. Since the transit time and the time constant of the sampling system depend on the sampling conditions, it is necessary to investigate the characteristics of sampling system before applied to exhaust gas measurement in engine. A unique method was designed to study the influence of the diameter of transfer sample line and operating conditions of the FRNDIR on transit time and time constant. A database of transit time and time constant was built up for different measured and simulated pressure conditions. The database can be used for correcting eventual $CO_2$ concentration measurement.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.61-63
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• 2002

This paper deals with the design of vaccum pump using moving magnet type linear oscillaory actuator based on the design procedure and the characteristic analysis. To improve the starting characteristic, the optimum spring constant is detected and redesigned. The parameter was calculated by Finite Element Method(FEM). In order to dynamic characteristic analysis. Time difference method with voltage and kinetic equation is used.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.1
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• pp.9-15
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• 2003

This Paper deals with the design of Moving Magnet type Linear Oscillatory Actuator(MM-LOA) using spring damper based on the design procedure and the characteristic analysis. MM-LOA is applied to variable load such as vaccum pump and compressor, The structure of piston type is selected to reduce a noise. MM-LOA has over-displacement in starting state because of the low inertia of mover To improve the starting characteristic, spring damper is used. The optimum spring constant of spring damper is detected and in consideration of spring damper, MM-LOA redesigned. The parameter is calculated by Finite Element Method(FEM). For the dynamic characteristic analysis, time differential method composed of voltage and kinetic equation is used. The propriety of the improved model is verified through the experimental results.

• Journal of Applied Reliability
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• v.18 no.2
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• pp.122-129
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• 2018

Purpose: This article develops an optimal reliability acceptance sampling plan for the case where the degradation quantity of the performance characteristic follows Weibull distribution. Method: For developing reliability acceptance sampling plans, the sample size and the acceptance constant are determined based on the accelerated characteristic of the test condition and the product. Results: The sample size and the acceptance constant are provided such that the constraints of the producer and the consumer risks are satisfied. Conclusion: Reliability acceptance sampling plans based on the accelerated degradation test method can be used for the quality control within a resonable amount of cost and time. In this article. an optimal reliability sampling plans are newly developed for this purpose.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.11-15
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• 2005

This paper presents a method to determine the characteristic polynomial of a closed loop all-pole system in order to obtain desired transient response in terms of the overshoot and speed (rising/settling time). The method adjusts the overshoot by doing some changes in the characteristic ratios of the Bessel-Thompson filter. The closed loop speediness is then tuned by suitable choice of the generalized time constant. Simulation results are presented to evaluate the achievements and make comparison with those of a similar method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.439-442
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• 2002

The interface between two different materials in the insulation systems is the weak-link in the underground power transmission systems, In this paper, Optimum conditions of the interface between Epoxy and EPDM is studied. The variation factor condition of interface is roughness of surface, spreading of oils, interfacial pressure and temperature. The breakdown times under the constant voltage below the breakdown voltage were also gained. The breakdown voltage at the after laying time equivalent to is calculated by the V-t characteristic and the inverse power law. When this is done, the characteristic life exponent n is used and the long time breakdown voltage can be evaluated.