• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.4 no.1
• /
• pp.39-45
• /
• 2011

In this paper, the design method of portable signal analysis system is proposed and the hardware module is implemented for operation of base stations based on a common platform for mobile WiMax. The new signal analysis method is implemented as two modules; a broadband RF module and a DSP based digital signal analysis module. The RF module performs the RF-IF down conversion and gain control. And the digital module measure the base staion signal. The differences of performance are insignificant in the experiment results performed through the comparison of other fixed-large system and proposed system.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.3
• /
• pp.451-456
• /
• 2020

In this paper, we studied the method of designing a embedded antenna for mounting on the JTDLS complete aircraft. The proposed antenna satisfies the MIDS-LVT operation frequency band and is designed as a broadband in consideration of expandability. As a result of the design, it was confirmed that the proposed antenna has similar electrical performance to the existing blade antenna and has broadband characteristics. As a result of EM analysis, the antenna was mounted on the top and bottom parts of the aircraft to check the mount of the aircraft, and it was confirmed that both the top and bottom parts had good radiation characteristics. The technology acquired through this study is judged to be applicable to the JTDLS completed aircraft.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.3
• /
• pp.264-273
• /
• 2005

Broadband power line communications have been receiving tremendous interest In recent years because this technology enables utilities to deploy a communication network over existing power line infrastructures. Despite the enormous potential, there is some skepticism about the technology and its commercial viability. In this paper, we investigate the performance characteristic of PLC through field test carried out in actual households. Also it addresses major field deployment aspects, such as range, coverage, the number of node for operation and maintenance.

• Current Optics and Photonics
• /
• v.6 no.1
• /
• pp.32-38
• /
• 2022

Erbium-doped fiber amplifiers (EDFAs) have saturated the technological market but are still widely used in high-speed and long-distance communication systems. To overcome EDFA saturation and limitations, its erbium-doped fiber is co-doped with other materials such as zirconia and bismuth. This article demonstrates and compares the performance using three different fibers as the gain medium for zirconia-erbium-doped fibers (Zr-EDF), bismuth-erbium-doped fibers (Bi-EDF), and commercial silica-erbium-doped fibers (Si- EDF). The optical amplifier was configured with a double-pass amplification system, with a broadband mirror at the end of its configuration to allow double-pass operation in the system. The important parameters in amplifiers such as optical properties, optical amplification and noise values were also examined and discussed. All three fibers were 0.5 m long and entered with different input signals: 30 dBm for low input and 10 dBm for high input. Zr-EDF turned out to be the most relevant optical amplifier as it had the highest optical gain, longest transmission distance, highest average flatness gain with minimal jitter, and relevant noise figures suitable for the latest communication technology.

• 한국정보통신설비학회:학술대회논문집
• /
• 2007.08a
• /
• pp.427-431
• /
• 2007

Applications in present-day mobile communication systems particularly require miniaturized dimensions and low-profiles of antenna in order to meet the mobile units. Thus, size reductions and bandwidth enhancements are becoming crucial design considerations for practical applications of microstrip antennas. The motivation of further experiments have been stepped to follow those studies for achieving compact and broadband, even multiplied operation modes, which are greatly increased with much attentions recently. To obtain broadband, single-feed, circularly polarized characteristics of microstrip antennas, a design with feed-line ought to be a factor of two. Usually, diagonally balanced-line feeds with hybrid coupler are employed to attain circular polarizations. We firstly formulated DGS (Defected Ground Structures) based operation principles of the entire microstrip components and therefore were able to derive impedance variance of feed-lines. After verifying corresponding experimental results, we targeted the frequency bands of UHF RFID (Ultra High Frequency Radio Frequency IDentification) and approximately of 0.4-2.4GHz have exhibited remarkable two resonance amplitudes as a dual band antenna. Our secondary researches were aimed to design quad band microstrip antenna which represents four resonance characteristics within the identical frequency bands as well. Microstrip patch has been meandered to lengthen the electrical paths, and the other design criteria with respecting physical parameters including radiation patterns and impedance bandwidths measurements will be described for verification. Advisable applications of these antennas can be GSM850, GSM900, GPS (L1-1575 and L2-1227) and UMTS-2110 of cellular systems, which extremely desire multiband and minimum size.

• Journal of the Korea Society of Computer and Information
• /
• v.22 no.9
• /
• pp.25-32
• /
• 2017

In this paper, we propose the softwareization of broadcasting system. Recently, the topic of industry is the fourth industrial revolution. The fourth industrial revolution is evolving from physical to virtualization. The Industrial Revolution is based on IT technology. Artificial Intelligence (AI), Big Data, and the Internet of Things, which are famous for Alpha Go, are based on software. Among IT, software is the main driver of industrial terrain change. The systemization of software on the basis of cloud environment is proceeding rapidly. System development through softwarization can reduce time to market lead time, hardware cost reduction and manual operation compared to existing hardware system. By developing and implementing broadcasting system such as IPTV based on cloud, lead time for opening service compared to existing hardware system can be shortened by more than 90% and investment cost can be saved by about 40%. In addition, the area of the system can be reduced by 50%. In addition, efficiency can be improved between infrastructures, shortening of trouble handling and ease of maintenance. Finally, we can improve customer experience through rapid service opening.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1318-1320
• /
• 2007

Fan noise prediction method is presented for air conditioning and/or cooling system applications where fan acts as an internal equipment having very complicated flow interaction with other various system components. The internal flow paths and distribution in the fan-applied systems such as computer or air conditioner are analyzed by using the FNM(Flow Network Modeling) with the flow resistances for flow elements of the system. Based on the fan operation point predicted from the FNM analysis results, the present fan noise model predicts overall sound power, pressure levels and spectrum. The predictions of the flow distribution, the fan operation and the noise level in electronic system by the present method are well agreed with 3-D CFD and actual noise test results.

• Journal of Satellite, Information and Communications
• /
• v.8 no.4
• /
• pp.12-16
• /
• 2013

This paper we introduce operated public test-bed satellite system configuration for satellite communications and usage for services via COMS(Communication, Ocean and Meteorological Satellite). According to trial public test-bed operation, the broadband multimedia services are expected to be available at the next generation VSAT services due to the increasing of Ka-band utilization. In addition, UHD broadcasting services via satellite is expected to improve the universal accessibility of broadcast services.

• Progress in Superconductivity and Cryogenics
• /
• v.16 no.3
• /
• pp.10-14
• /
• 2014

Due to continuous increase of electric power consumption, couple of resolutions for improving accuracy in power system like line separation are being studied. The increase of the power demand can cause problems such as supply difficulties of the electricity and broadband outages, failure, etc. When a fault occurs in the power system, a fault current also increases. Fault current creates problems like reduction of lifespan and failure on the power system. In order to resolve these problems, the reduction of initial fault current using the characteristics of superconducting element was applied to fault current limiter. We applied the system to high speed fault current limiter. We found that the superconducting element effectively reduced initial fault current and the fault current was limited by changing operation of high speed interrupter.

• Proceedings of the IEEK Conference
• /
• 2007.07a
• /
• pp.177-178
• /
• 2007

WiBro system provides reliable broadband communication services for mobile and portable subcribers. It allows interference-free reception under the conditions of multipath propagation and transmission errors. Thus, powerful channel-error correction ability Is required. CC/CTC Decoder which Is mandatory for WiBro system needs lots of computations for real-time operation. So, it is desired to design a CC/CTC Decoder having highly optimized hardware scheme for low latency operation under high data rates. This paper proposes an efficient CC/CTC Decoder structure for high data rate WiBro system. Particularly, the proposed CTC Decoder architecture reduces decoding delay by applying pipelining and multiple decoding blocks. Simulation results show that reduction of about 80% of processing time is enabled with the proposed CC/CTC Decoder despite of increase in are.