• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1140-1143
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• 2009

디지털 방송기술과 네트워크 통신기술의 발전은 방송 산업의 증가, 서비스의 다양화 그리고 방송 콘텐츠의 대용량화를 가져오게 되었다. 일반적으로 방송 시스템은 저장된 파일의 방송, 카메라나 캠코더와 같은 하드웨어를 통하여 인코딩된 데이터의 방송, MPEG-TS로 인코딩 및 패킷타이징된 데이터의 방송들이 대표적이다. 이러한 방송시스템에는 개인의 PC스크린을 실시간 방송하기위한 기법이 필요할 것이며. 본 논문에서는 개인화면 실시간 방송을 위한 PC 스크린 캡처 모듈, 전송을 위한 인코딩 모듈, 다중 송수신을 위한 전송모듈 등의 시스템에 필요한 복합적인 기법을 구현하였다. 제안한 시스템은 이러한 모듈들을 통합하여 PC 스크린을 실시간으로 전송하여 시청할 수 있도록 하였다.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.4
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• pp.23-31
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• 2018

This paper presented the implementation and design of the 2T-2R wireless HD video streaming systems over 1.7 GHz frequency band using 3GPP LTE-TDD standard on NI USRP RIO SDR platform. The baseband of the system used USRP RIO that are stored in Xilinx Kintex-7 chip to implement LTE-TDD transceiver modem, the signal that are transmitted from USRP RIO up or down converts to 1.7 GHz by using self-designed 1.7 GHz RF transceiver modules and it is finally communicated HD video data through self-designed 2x9 sub array antennas. It is that communication method between USRP RIO and Host PC use PCI express x4 to minimize delay of data to transmit and receive. The implemented system show high error vector magnitude performance above 32 dBc and to transmit and receive HD video in experiment environment anywhere. The proposed hybrid beam forming system could be used not only in the future 5G mobile communication systems under 6 GHz frequency band but also in the systems over 6 GHz frequency band like ones in mmWave frequency bands.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.162-170
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• 2022

In this paper, the phased-array transceiver (TRX) channel amplitude and phase calibration method for a radar wind profiler (RWP) based on the 256 active phased array is discussed. Without the additional module, the TX and RX calibration paths were secured using couplers and switches in the TRX front ends and the TRX switching duplexers, and the amplitude and phase of the 256 TRX were calibrated using a gain and phase detector. The beam widths and side lobes of five beams (vertical, east, west, south, and north) of the calibrated 256 active phased array antenna were confirmed by a near-field which agreed well with the simulation results. The proposed calibration method can be easily applied to a system based on an active phased array operated in an outdoor environment.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.3
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• pp.98-109
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• 2002

Bluetooth technology is a publicly available specification proposed for Radio Frequency (RF) communication for short-range :1nd point-to-multipoint voice and data transfer. It operates in the 2.4㎓ ISM(Industrial, Scientific and Medical) band and offers the potential for low-cost, broadband wireless access for various mobile and portable devices at range of about 10 meters. In this paper, we describe the structure and the test results of the bluetooth baseband module with direct memory access method we have developed. This module consists of three blocks; link controller, UART interface, and audio CODEC. This module has a bus interface for data communication between this module and main processor and a RF interface for the transmission of bit-stream between this module and RF module. The bus interface includes DMA interface. Compared with the link controller with FIFOs, The module with DMA has a wide difference in size of module and speed of data processing. The small size module supplies lorr cost and various applications. In addition, this supports a firmware upgrade capability through UART. An FPGA and an ASIC implementation of this module, designed as soft If, are tested for file and bit-stream transfers between PCs.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.3
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• pp.93-98
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• 2005

Silicon bipolar transistors (Si-BJT) are widely used in the telecommunication system such as short range wireless control and wireless indoor voice communication system. New modeling method for the internal current source model of Si-BJT is proposed. The proposed method based on new thermal resistance extraction method and new analytical expressions for the current source parameters of Si-BJT. The proposed method can directly extract the model parameters without any optimization procedure which is adopted in the conventional modeling method. The proposed method is applied to 5 finger $0.4\times20[{\mu}m^2]$ and the model shows good prediction of the measured data in $3[\%]$ of errors proving the validity of this method.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.2
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• pp.249-254
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• 2019

A Digital Transmitter/Receiver Module(DTRM), which is an essential part in active phased-array radar systems, generates a high heat density, and needs to be properly cooled for stable operation. A tile-type DTRM that is a stacking structure of multi-layer components was modeled with simplification and heat dissipation characteristics of the DTRM model were studied using computational fluid dynamics(CFD) simulations. Most of the heat was dissipated by the heat conduction through the cold plate, but the heat transfer by the forced convection on top of the DTRM also was found to play an important role in the thermal management. Under the given conjugated heat transfer environment, the DTRM was confirmed to secure a stable operating temperature range.

• Journal of IKEEE
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• v.20 no.3
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• pp.251-259
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• 2016

This paper describes that how to enhance the robustness of semiconductor TRM(Transmitter and Receiver Module) through the bias sequencing and tuning the switching time. Previous circuit designs focused on improving the MDS(Minimum Detection Signal) performance. Because TRM has critical problem which transmission output signal leak into receiver by it's compact design. Under this condition, TRM was frequently broken down within the MTBF(Mean Time Between Failure). This study proposes the bias sequencing and tuning the switching time to improve above problem. At first, we collected major failure symptom and infer it's cause. Second, we demonstrated it's effect by derive the improvement method and apply it to our system. And finally we can convinced that the proposed method clear the frequent failure problem with its lack of isolation.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.672-676
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• 2009

Recently, intelligent surveillance camera systems are needed popularly. However, current researches are focussed on improvement of a single module rather than implementation of an integrated system. In this paper, we implemented a wireless surveillance camera system which is composed of face detection, and using motion sensor. In our implementation, we used a camera module from SHARP, a pair of wireless video transmission module from ECOM, a pair of ZigBee RF wireless transmission module from ROBOBLOCK, and a motion sensor module (AMN14111) from PANASONIC. We used OpenCV library for face dection and MFC for implement software. We identified real-time operations of face detection, PTT control, and motion sensor detecton. Thus, the implemented system will be useful for the applications of remote control, human detection, and using motion sensor.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.3
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• pp.1-11
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• 1999

It is now common practice to utilize the quadrature RF coils to improve the signal-to-noise ratio (SNR) in the Magnetic Resonance Imaging (MRI) System. In addition, to make such an available SNR improvement, it is mandatory to use a well-designed quadrature coupler, which facilitates a perfect 3-dB coupling and quadrature-phase shift. However, the four ports matching condition has to be well considered during the RF excitation and the signal detection period. This work investigates the effects of such a mismatching condition (especially, due to patient) from the analysis, simulation, and real implementation and firstly proposes dynamic loading technique for a quadrature coupler and transmitting/receiving switch module to minimize a patient mismatching and enhance a system reliability. Also, we designed and implemented the quadrature coupler and transmitting/receiving switch module using microstrip. As a result, the SNR of our MRI system using the microstrip quadrature coupler and transmitting/receiving switch module with dynamic load increases 3 dB compared with the old one using USA quadrature switch. Also, the power capability of quadrature coupler and transmitting/receiving switch module is 5-kw peak power. Considering power loss and reduction of size, we used a RT/duroid 6010 substrate with high permittivity and for simulation we use Compact Software.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.92.1-92.1
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• 2010

본 기술개발은 기존 태양추적기의 구조를 크게 변화시킬 수 있는 무선망 활용 태양추적기 개발에 관한 내용이다. 기존의 태양추적기는 태양광어레이에 스탠드얼론 시스템으로 부착되어 태양추적 및 관련 제어기능을 수행한다. 그러나 본 무선망활용 태양추적기는 PC와 태양광어레이가 지그비 무선망으로 연결되는 구조이다. 무선망을 활용함으로서 기존 태양추적기 대비 제어모듈의 역할이 매우 단순화되어 장치의 강건함, 내구성 및 경제성이 증가되는 효과가 있다. 무선망을 활용함으로서 태양광에레이 측은 무선데이터 송수신 기능과 모터제어 부분만 구현되어도 되며 나머지 기능들은 PC에서 처리해서 무선으로 태양광에레이 모듈에게 전달된다. 또한 고가의 센서 등도 PC에만 구현되고 필요한 데이터는 PC에서 처리하고 계산해서 무선으로 태양광어레이에게 전달하는 구조이다. 그리고 태양추적을 위한 정밀한 자동제어 알고리즘도 PC에서는 충분히 구현할 수 있으며 이를 수행한 후 필요 데이터를 태양광어레이 모듈에게 무선으로 전달한다. 본 기술개발 내용에 대한 시제품이 완성단계에 있으며 필드테스트 수행을 준비하고 있다.