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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Electronics and Telecommunications Research Institute
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Volume & Issues
Volume 27, Issue 6 - Dec 2005
Volume 27, Issue 5 - Oct 2005
Volume 27, Issue 4 - Aug 2005
Volume 27, Issue 3 - Jun 2005
Volume 27, Issue 2 - Apr 2005
Volume 27, Issue 1 - Feb 2005
Selecting the target year
A Novel Mobile Antenna for Ku-Band Satellite Communications
Park, Ung-Hee ; Noh, Haeng-Sook ; Son, Seong-Ho ; Lee, Kyong-Hee ; Jeon, Soon-Ik ;
ETRI Journal, volume 27, issue 3, 2005, Pages 243~243
A mobile antenna for multimedia communications with Ku-band geostationary satellite KOREASAT-3 and JSAT-2A is presented. The forward link of the satellite communication is 11.7 to 12.75 GHz, and the return link is 14.0 to 14.5 GHz. The mobile antenna is designed to be a stair structure using 24 active phased array elements in order to provide a low profile, and to be at a non-periodic array distance using the genetic algorithm. Also, the designed antenna uses the double beam forming method for stable satellite tracking. The fabricated mobile antenna is examined using various experiments to confirm its capability for practical application. From the measured results, the fabricated mobile antenna system is confirmed to have a good performance.
Dice-Five Polarization-Agile Corner-Fed Patch Array Antenna
Vallecchi, Andrea ;
ETRI Journal, volume 27, issue 3, 2005, Pages 250~250
A novel planar polarization-agile microstrip subarray is proposed and its performance assessed by a thorough numerical investigation. The subarray consists of five square patches with a central element, directly coupled to a pair of microstrip feed lines by a cross-shaped aperture, which spreads the power outwards to the other patches through a network of suitable connections. By properly exciting the antenna at its input ports, any kind of polarization of the radiated field can be accomplished with fairly low cross-polarization levels. Moreover, since only two feed lines are required to drive the whole subarray, polarization agility is simply and attractively achieved by a single phase-shift circuit. The design concept is described and the results of the analyses and simulations performed by two completely independent full-wave approaches are presented and discussed.
Sliced Multi-modulus Blind Equalization Algorithm
Abrar, Shafayat ; Axford, Roy A. Jr. ;
ETRI Journal, volume 27, issue 3, 2005, Pages 257~257
Many multi-modulus blind equalization algorithms (MMA) have been presented in the past to overcome the undesirable high misadjustment exhibited by the well-known constant modulus algorithm. Some of these MMA schemes, specifically tailored for quadrature amplitude modulation (QAM) constellations, have also been proved to fix the phase offset error without needing any rotator at the end of the equalizer stage. In this paper, a new multi-modulus algorithm is presented for QAM signals. The contribution lies in the technique to incorporate the sliced symbols (outcomes of decision device) in the multi-modulus-based weight adaptation process. The convergence characteristics of the proposed sliced multi-modulus algorithm (S-MMA) is demonstrated by way of simulations, and it is shown that it gives better steady-state performance in terms of residual inter-symbol interference and symbol-error rate. It has also been shown that the proposed algorithm exhibits lesser steady-state misadjustment compared to the best reported MMA.
Study of Optical Transmission Performance in IP-over-WDM Networks Based on FSK/ASK Combined Modulation Format
Xiangjun, Xin ; Andre, Paulo Sergio de Brito ; Teixeira, Antonio Luis Jesus ; Monteiro, Paulo P. ; Rocha, Jose R. F. da ;
ETRI Journal, volume 27, issue 3, 2005, Pages 267~267
The transmission performance of optical labeling based on a combined frequency shift keying/amplitude shift keying (FSK/ASK) format is studied by numerical simulation. The simulation demonstrates that the bit-error ratio (BER) characteristic of an ASK signal is limited by the extinction ratio, received optical power, and dispersion, simultaneously. However, an FSK signal is mainly limited by the extinction ratio (ER) and received optical power when the peak spectrum, which is used to detect the FSK signal, is relatively narrow.
PN Sequence Generation from 2-D Array of Shift Registers
Kim, Hyun-Jung ; Lee, In-Kyu ; Kim, Woon-Kyung M. ;
ETRI Journal, volume 27, issue 3, 2005, Pages 273~273
Toward code division multiple access (CDMA) communications and data protection, we propose and analyze pseudorandom noise (PN) sequences generated from a 2-dimensional array structure of shift-registers. For any positive integers m and n, we construct PN sequences of period
array of registers and show that we can generate all shifted PN sequences as required by IS-95x with the proper linear combination of available sequences.
A Calibration Technique for a Two-Axis Magnetic Compass in Telematics Devices
Cho, Seong-Yun ; Park, Chan-Gook ;
ETRI Journal, volume 27, issue 3, 2005, Pages 280~280
This paper presents an efficient algorithm for using the two-axis magnetic compass in portable devices. The general magnetic compass module consists of a three-axis magnetic compass and a two-axis inclinometer to calculate tilt-compensated azimuth information. In this paper, the tilt error is compensated using just a two-axis magnetic compass and two-axis accelerometer. The third-axis data of the magnetic compass is estimated using coordinate information that includes the extended dip angle and tilt information. The extended dip angle is estimated during the normalization process. This algorithm can be used to provide the tilt-compensated heading information to small portable devices such as navigation systems, PDAs, cell phones, and so on.
Computational Implementation of Asymmetric Integral Imaging by Use of Two Crossed Lenticular Sheets
Shin, Dong-Hak ; Cho, Myung-Jin ; Kim, Eun-Soo ;
ETRI Journal, volume 27, issue 3, 2005, Pages 289~289
We propose an asymmetric integral imaging method to adjust the resolution and depth of a three-dimensional image. Our method is obtained by use of two lenticular sheets with different pitches fabricated under the same F/#. The asymmetric integral imaging is the generalized version of integral imaging, including both conventional integral imaging and one-dimensional integral imaging. We present experimental results to test and verify the performance of our method computationally.
Potential Anomaly Separation and Archeological Site Localization Using Genetically Trained Multi-level Cellular Neural Networks
Bilgili, Erdem ; Goknar, I. Cem ; Albora, Ali Muhittin ; Ucan, Osman Nuri ;
ETRI Journal, volume 27, issue 3, 2005, Pages 294~294
In this paper, a supervised algorithm for the evaluation of geophysical sites using a multi-level cellular neural network (ML-CNN) is introduced, developed, and applied to real data. ML-CNN is a stochastic image processing technique based on template optimization using neighborhood relationships of the pixels. The separation/enhancement and border detection performance of the proposed method is evaluated by various interesting real applications. A genetic algorithm is used in the optimization of CNN templates. The first application is concerned with the separation of potential field data of the Dumluca chromite region, which is one of the rich reserves of Turkey; in this context, the classical approach to the gravity anomaly separation method is one of the main problems in geophysics. The other application is the border detection of archeological ruins of the Hittite Empire in Turkey. The Hittite civilization sites located at the Sivas-Altinyayla region of Turkey are among the most important archeological sites in history, one reason among others being that written documentation was first produced by this civilization.
A Comparative Study of a Dielectric-Defined Process on AlGaAs/InGaAs/GaAs PHEMTs
Lim, Jong-Won ; Ahn, Ho-Kyun ; Ji, Hong-Gu ; Chang, Woo-Jin ; Mun, Jae-Kyoung ; Kim, Hae-Cheon ; Cho, Kyoung-Ik ;
ETRI Journal, volume 27, issue 3, 2005, Pages 304~304
We report on the fabrication of an AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) using a dielectric-defined process. This process was utilized to fabricate
T-gate PHEMTs. A two-step etch process was performed to define the gate footprint in the
was etched either by dry etching alone or using a combination of wet and dry etching. The gate recessing was done in three steps: a wet etching for removal of the damaged surface layer, a dry etching for the narrow recess, and wet etching. A structure for the top of the T-gate consisting of a wide head part and a narrow lower layer part has been employed, taking advantage of the large cross-sectional area of the gate and its mechanically stable structure. From s-parameter data of up to 50 GHz, an extrapolated cut-off frequency of as high as 104 GHz was obtained. When comparing sample C (combination of wet and dry etching for the
) with sample A (dry etching for the
), we observed an 62.5% increase of the cut-off frequency. This is believed to be due to considerable decreases of the gate-source and gate-drain capacitances. This improvement in RF performance can be understood in terms of the decrease in parasitic capacitances, which is due to the use of the dielectric and the gate recess etching method.
Chromatic Dispersion Compensation via Mid-span Spectral Inversion with Periodically Poled
Wavelength Converter at Low Pump Power
Kim, Min-Su ; Ahn, Joon-Tae ; Kim, Jong-Bae ; Ju, Jung-Jin ; Lee, Myung-Hyun ;
ETRI Journal, volume 27, issue 3, 2005, Pages 312~312
Mid-span spectral inversion (MSSI) has to utilize high optical pump power, for its operation principle is based on a nonlinear optical wavelength conversion. In this paper, a low pump-power operation of MSSI-based chromatic dispersion compensation (CDC) has been achieved successfully, for the first time to our knowledge, by introducing a noise pre-reduction scheme in cascaded wavelength conversions with periodically poled
waveguides at a relatively low operation temperature. As preliminary studies, phase-matching properties and operation-temperature dependence of the wavelength converter (WC) were characterized. The WC pumped at 1549 nm exhibited a wide conversion bandwidth of 59 nm covering the entire C-band and a conversion efficiency of -23.6 dB at 11 dBm pump power. CDC experiments were implemented with 2.5 and 10 Gb/s transmission systems over 100 km single-mode fiber. Although it is well-known that the signal distortion due to chromatic dispersion is not critical at a 2.5 Gb/s transmission, the clear recovery of eye patterns was identified. At 10 Gb/s transmission experiments, eye patterns were retrieved distinctly from seriously distorted ones, and notable improvements in bit-error rates were acquired at a low pump power of 14 dBm.
Estimation of Electrical Parameters of OD Organic Semiconductor Diode from Measured I-V Characteristics
Moiz, Syed Abdul ; Ahmed, Mansoor M. ; Karimov, Kh. S. ;
ETRI Journal, volume 27, issue 3, 2005, Pages 319~319
In this paper the effect of temperature on the electrical properties of organic semiconductor disperse orange dye 25 (OD) have been examined. Thin films of OD have been deposited on
substrates using a centrifugal machine. DC current-voltage (I-V) characteristics of the fabricated devices
have been evaluated at varying temperatures ranging from 40 to
. A rectification behavior in these devices has been observed such that the rectifying ratio increases as a function of temperature. I-V characteristics observed in
devices have been classified as low temperature
and high temperature characteristics (approximately
). Low temperature characteristics have been explained on the basis of the charge transport mechanism associated with free carriers available in OD, whereas high temperature characteristics have been explained on the basis of the trapped space-charge-limited current. Different electrical parameters such as traps factor, free carrier density, trapped carrier density, trap density of states, and effective mobility have been determined from the observed temperature dependent I-V characteristics. It has been shown that the traps factor, effective mobility, and free carrier density increase with increasing values of temperature, whilst no significant change has been observed in the trap density of states.
Disparity-Compensated Stereoscopic Video Coding Using the MAC in MPEG-4
Cho, Suk-Hee ; Yun, Kug-Jin ; Ahn, Chung-Hyun ; Lee, Soo-In ;
ETRI Journal, volume 27, issue 3, 2005, Pages 326~326
The MPEG-4 multiple auxiliary component (MAC) is a good mechanism to achieve one-stream stereoscopic video coding. However, there is no syntax or semantics for the residual texture data of the disparity-compensated image in the current MAC. Therefore, we propose a novel disparity-compensated coding method using the MAC for stereoscopic video. We also define a novel MAC semantics in MPEG-4 so as to support the proposed coding algorithm. The major difference between the existing and proposed coding methods using the MAC is the addition of the residual texture coding.
An Efficient Representation Method for ICLD with Robustness to Spectral Distortion
Beack, Seung-Kwon ; Seo, Jeong-Il ; Kang, Kyung-Ok ; Hanh, Min-Soo ;
ETRI Journal, volume 27, issue 3, 2005, Pages 330~330
The Inter-Channel Level Difference (ICLD) is a cue parameter to estimate spectral information in a binaural cue coding that has been recently in the spotlight as a multichannel audio signal compression technique. Even though the ICLD is an essential parameter, it is generally distorted by quantization. In this paper, a new modified ICLE representation method to minimize the quantization distortion is proposed by adopting a flexible determination of the reference channel and the unidirectional quantization. Our experimental result confirms that the proposed method improves the multichannel audio output quality even with the reduced bit-rate.
Noise Suppression of Spectrum-Sliced WDM-PON Light Sources Using FP-LD
Lee, Woo-Ram ; Cho, Seung-Hyun ; Park, Jae-Dong ; Kim, Bong-Kyu ; Kim, Byoung-Whi ;
ETRI Journal, volume 27, issue 3, 2005, Pages 334~334
We improved the performance of the spectrum-sliced light source for wavelength-division-multiplexed passive optical networks by employing a Fabry-Perot laser diode(FP-LD). We found that the FP-LDs can suppress the intensity noise as significantly as using a gain-saturated semiconductor optical amplifier. The transmission characteristics were measured and analyzed in both conditions with and without employing an FP-LD.
Thermal Characteristics of a Laser Diode Integrated on a Silica-Terraced PLC Platform
Kim, Duk-Jun ; Han, Young-Tak ; Park, Yoon-Jung ; Park, Sang-Ho ; Shin, Jang-Uk ; Sung, Hee-Kyung ;
ETRI Journal, volume 27, issue 3, 2005, Pages 337~337
A spot-size converted Fabry-Perot laser diode (LD) was flip-chip bonded to a silica-terraced planar lightwave circuit(PLC) platform to examine the effect of the silica terrace on the heat dissipation of the LD module. From the measurement of the light-current characteristics, it was discovered that the silica terrace itself is not a strong thermal barrier, but the encapsulation of the integrated LD with an index-matching polymer resin more or less deteriorates the heat dissipation.