• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.5
• /
• pp.230-237
• /
• 2003

Current mode control has been used for DC to DC converters for over twenty years. There are many different control schemes which use the inductor current signal in one way or another to control the DC to DC converter. In this paper, the state space averaging technique is applied for the analysis of flyback type current mode control circuit. We made real converter for the guarantee of stable output characteristic and proper design of feedback circuit. The validity of proposed method is verified from test result. The improvement of stability is confirmed by sinusoidal signal injection method with isolated transformer. It is known that phase margin is sufficient and gain crossover frequency fc is early 1/5 of switching frequency, fs, from the experimental result with frequency response analyzer.

• Proceedings of the KIEE Conference
• /
• 2001.07b
• /
• pp.1154-1156
• /
• 2001

This paper presents the implementation of a positon sensorless vector control system of a PM linear synchronous motor by sliding mode observer based on TMS320F240 DSP controller. Sliding mode observer estimates the secondary velocity and position based on the measurement of current, and it shows very robust characteristic to parameter variation. Therefore, it improves the system performance deterioration caused by system parameter variations. Simulation and experimental considerations are presented to confirm the applicability of sliding mode observer to the sensorless position control of PMLSM.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.48 no.7
• /
• pp.28-34
• /
• 2011

Radiation characteristics of a dual-mode inductor loaded patch antenna using zeroth order resonance and half wavelength resonance are investigated. The isolation between two radiation patterns from the two different modes is improved by increasing the forward radiation and decreasing the horizontal radiation of half wavelength resonance mode. The frequency difference between the two resonant frequencies increases as the dielectric constant of the antenna substrate decreases and the operating frequency increases.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.202-207
• /
• 2002

This paper deals with a novel shunted actuator, which has a capability to suppress multi-mode vibration amplitudes by using a pair of piezoceramic patches. In order to describe the characteristic behaviors of shunted dampers connected with a series and a parallel resistor-negative capacitive branch circuit, the stiffness ratio and loss factor with respect to the non-dimensional frequency are considered. To obtain a guideline model of a piezo/beam system connected with a series and a parallel resistor-negative capacitor branch circuit, the governing equations of motion is derived through Hamiltons principle and a piezo sensor equation as well as a shunt damping matrix is developed. The theoretical analysis shows that the shunted actuator developed in this study can significantly reduce multiple-mode vibration amplitudes simultaneously over the whole structural frequency range.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2012.10a
• /
• pp.792-798
• /
• 2012

This study shows the vibration characteristics of an actuator with six wire-suspensions, used in optical pickups of optical disc drives (ODDs). In this paper, the vibration characteristics of this beam structure is induced mathematically. To obtain vibration modes of focusing direction, the vibration analysis is achieved in lateral and longitudinal directions of the structure. The accuracy of induced vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode shapes can be modified by changing design parameters in mathematical expressions.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.22 no.11
• /
• pp.1128-1136
• /
• 2012

This paper analyzes the vibration characteristics of an optical pickup actuator, which has six wire-suspensions and is used in optical disc drives(ODDs). The vibration characteristics of the actuator is mathematically described by analyzing its beam configuration and motion condition confined to lateral and longitudinal directions of the beams. The accuracy of the vibration characteristics is proved by comparing mode frequencies with a finite element analysis. Finally, it is shown that mode frequencies and shapes can be modified by changing design parameters in mathematical expressions.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.13 no.5
• /
• pp.49-54
• /
• 2013

We designed a burst mode optical receiver for 1.25Gbps PON(Passive Optical Network), fabricated it using $0.8{\mu}m$ BiCMOS foundry. We minimized the loss of the data in the front of the burst by reducing AGC(Automatic Gain Control) signal generation time using an exponential amplifier. We confirmed that AGC of the burst mode optical receiver functioned well and showed good performance in measurement. However, although the eye of the eye pattern was opened the jitter characteristic was deteriorated due to the heavy waveform distortion.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.22 no.6
• /
• pp.46-52
• /
• 1985

A theoretical study of mutual coupling effects between two H-plane coupled microstrip patch antennas is presented. The radiation resistance and slot capacitance of a single micro-strip patch are calculated. To investigate the mutual coupling effects, the even and odd mode characteristic impedance and effective dielectric constants are obtained using the coupled microstrip line model. The S-parameter matrix elements 511,512 are used to study the mutual coupling e(facts in S-band frequency ranges for various patch spacings. Theoretical results and measurements are in good agreement.

• Structural Engineering and Mechanics
• /
• v.8 no.2
• /
• pp.181-191
• /
• 1999

This paper presents an investigation of the mode localization and frequency loci veering phenomena in an aircraft with disordered external stores. Two theoretical analyses are carried out to study the occurring mechanism of the two phenomena: condensation technique in the subspace spanned by modes of interest and geometric mapping theory in the complex plane. Two simple criteria for predicting the occurrence of the mode localization and frequency loci veering are put forward. The prediction of the phenomena by our theoretically proposed criteria is in good agreement with that obtained through numerical calculations of characteristic solutions of the disordered system.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.31A no.10
• /
• pp.39-47
• /
• 1994

In this paper, by modeling the Multilayer-Multiconductor Transmission Line(MMTL) with the characteristic parameters-effective dielectric constant, eigen modal voltages, characteristic impedances at each mode, pulse propagation characteristics of MMTL network are simulated. Transmission line modelling is performed in frequency domain, then time domain resposes are obtained by transforming the frequency domain response using fast Fourier transform.