• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.1
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• pp.18-27
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• 2004

In this paper, we presents an analytical simulation procedure for evaluation in baseband digital modulated signals distortions in the present of RF power amplifier(SSPA) nonlinear behavior and backoff operations of OFDM wireless transmission system. we obtained the optimum nonlinear transfer function of designed SSPA with the SiGe HBT bias currents of OFDM multi-channel wireless transmission system and compared this transfer function to SSPA nonlinear modeling functions mathematically, we finds optimum bias conditions of designed SSPA. With the derived nonlinear modeling function of SSPA, We analysed the PSD characteristics of in-band and out-band output powers of SSPA EVM measurement results of distorted constellation signals with the input power levels of SSPA. The results of paper can be applied to find the SSPA linearly with optimum bias currents and determine the SSPA input backoff bias for AGC control circuits of SSPA.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.415-422
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• 2004

DSRC provides high speed radio link between Road Side Equipment and On-Board Equipment within the narrow communication area. In this paper, a 5.8 GHz down-conversion mixer for DSRC communication system was designed and fabricated using 0.8 ${\mu}{\textrm}{m}$ SiGe HBT process technology and RF/LO matching circuits, RF/LO input balun circuits, and If output balun circuit were all integrated on chip. The chip size of fabricated mixer was 1.9 mm${\times}$1.3 mm and the measured performance was 7.5 ㏈ conversion gain, －2.5 ㏈m input IP3, 46 ㏈ LO to RF isolation, 56 ㏈ LO to IF isolation, current consumption of 21 mA for 3.0 V supply voltage.

• Proceedings of the KAIS Fall Conference
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• 2009.12a
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• pp.190-193
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• 2009

The most essential element in wireless sensor network is wireless sensor node which collects environmental information and transmits it to the user application systems. Recently, due to the technological advancement, wireless sensor nodes are become smaller, more intelligent and less power consuming. Especially, SoC(System-on-Chip) technology, which unifies the MCU, RF module, memory and other element inside one chip, plays an important part for miniaturization of sensor node, hence reduces the manufacturing expenses. In this paper, we have designed a miniaturized wireless sensor node for wireless sensor network using commercial SoC technology and discussed about some application scenario and additional considerations.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.2
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• pp.131-137
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• 2000

In this paper, as a compatible software radio transmission system, Digital-Radio conversion system which can directly change the digital signal generated by the logic circuit into radio signal is proposed. By the vector synthesis method, the digital signals can change directly into radio signal. If such a circuit is realized, RF circuit and an antenna can be composed by the simple one device, and the radio is directly controlled and performed by the software processing which is the essence of software radio. This Digital-Radio conversion system of this paper give many number of communication channels being offered by PN code and offer a hardware design flexibility by digitization, therefore it decrease the percentage ratio of hardware of system and give a more flexible function of software basis. In this paper, the principle of digital to radio signal generation algorithm is explained and the performance characteristics of proposed algorithm is shown in time base by the computer simulation method.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.1-10
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• 2023

In this paper, the design and implementation of the long-distance wireless transmission technology of high-definition video using domestic wireless communication technology for the existing wired-based CCTV surveillance system and IP camera system was evaluated for performance. The interworking test between the wireless multi-IP camera transmission terminal device and the wireless communication RF module, and the wireless multi-IP camera-based video transmission system integration interworking test confirm the module interworking suitability during video transmission.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.7
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• pp.1165-1171
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• 2006

In this paper, we designed radio data transceiver to control the machine or equipments for automation in local areas. The designed module can transmit data with 153.6Kbps and uses 424MHz RF carrier to transmit data in the ISM band regulation. It has a processor, CPLD chip of the Altera Company, to control the data in transmitting and receiving. The processor is implemented by programming with VHDL. We will make this module with compact in dimension and higher data rate and apply to RFID technology.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.348-351
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• 2000

In order to enact the technical standard of RF(Radio Frequency) in domestic, this paper analyzes the trends and the technical specifications of high performance radio local area network, for example HIPERLAN(Europe), U-Nll(U.S.A), broadband mobile access system(Japan). The contents of this paper are helpful to make a rule for the desirable national technical standard of high performance radio local area network.

• Electronics and Telecommunications Trends
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• v.16 no.5 s.71
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• pp.101-112
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• 2001

여러 가지 확산방식 가운데 2.4GHz 대역에서 블루투스, 무선 LAN 등에 적용되고 있는 FHSS(Frequency Hopping Spread Spectrum) 방식을 사용하는 무선기기들에 대하여 미국과 유럽 그리고 일본에서 정하고 있는 기술기준 또는 표준에 관하여 개괄적으로 살펴보았다. 지역별로 정하고 있는 기술기준과 연계하여 각각의 기술기준 또는 표준의 항목들이 의미하는 바를 측정의 관점에서 기술하였으며, 다양한 측정 방법들이 갖는 기술적인 내용에 대하여도 포괄적으로 분석하였다. 마지막으로 최근 국내에서도 FHSS 방식을 사용하는 무선기기들에 대한 기술기준이 개정 고시됨에 따라 국내의 기술기준의 개정 배경과 의미를 외국 기술기준의 내용과 비교하여 설명하였으며, 그 측정 방법에 내포된 의미와 차이점들을 분석하였다.

• The Magazine of the IEIE
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• v.44 no.7
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• pp.47-54
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• 2017

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11A
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• pp.909-917
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• 2009

In this paper, we proposed and implemented the method to efficiently generate TDD synchronization signal and the digital circuit for the RF repeater which can eliminate the shadow region in the wireless communication field using the time division duplex (TDD) method. After detecting the TDD signal from the transmitted or received RF signal, the detected TDD signal is fed to the RF repeater for the normal operation. The proposed technique detects the envelop of the downlink signal and amplifies the detected envelop, and then restores the degraded envelop with the proposed digital filtering method. Finally the restored envelop is manipulated to the TDD synchronization signal. Our focus on the proposed algorithm is to develop it with simple feature and low cost but robust performance. The proposed scheme was implemented to the integrated system which has both RF and digital circuit and tested under the same condition with the commercial WiBro service.