• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.259-262
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• 2003

In this paper, we designed and implemented digital wireless audio system with embedded RTOS using Bluetooth. Transmitter is consisted of a Settopbox, FIFO for interface block, Microprocessor(ARM7TDMI), UART driver and Bluetooth module. Receiver is consisted of a Microprocessor, AC-3 decoder, Bluetooth module and a Speaker with Amp. We programed Bluetooth protocal stack of HCI, L2CAP, and RFCOMM, so that Bluetooth module interacts with CPU.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.1
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• pp.11-18
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• 2010

GNSS(Global Navigation Satellite System) Ground Station performs GNSS signal acquisition and processing. This system generates error correction information and distributes them to GNSS users. GNSS Ground Station consists of sensor station which contains receiver and meteorological sensor, monitoring and control subsystem which monitors and controls sensor station, control center which generates error correction information, and uplink station which transmits correction information to navigation satellites. Monitoring and control subsystem acquires and processes navigation data from sensor station. The processed data is transmitted to GNSS control center. Monitoring and control subsystem consists of data acquisition module, data formatting and archiving module, data error correction module, navigation determination module, independent quality monitoring module, and system maintenance and management module. The independent quality monitoring module inspects navigation signal, data, and measurement. This paper introduces independent quality monitoring and performs the analysis using measurement data.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.6
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• pp.1513-1518
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• 2012

This paper is implemented media transmission system of VLC transmitter and receiver module using LED of White lighting that is based on PC module and to transmission technology for performance analysis. To realize LED visible light communication receiver is used 1~12 LED light-emitting device and transmitter is used a variable sensor. Developed initial distance of the tranceiver is more than 0~1m for LED VLC and the overall system transmission speed is achieved on variable having Visible light media transmission system. Composition to PC module with LED module and infrared sensor for performance analysis, predict and analyze the communication distance, check about the possibility of application methods. Measure each performance when the lens wearing and not wearing in order to increase the overall efficiency of the LED module, can know that increase efficiency of approximately 20%.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.235-240
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• 2006

Ionospheric scintillation induces a rapid change in the amplitude and phase of radio wave signals. This is due to irregularities of electron density in the F-region of the ionosphere. It reduces the accuracy of both pseudorange and carrier phase measurements in GPS/satellite based Augmentation system (SBAS) receivers, and can cause loss of lock on the satellite signal. Scintillation is not as strong at mid-latitude regions such that positioning is not affected as much. Severe effects of scintillation occur mainly in a band approximately 20 degrees on either side of the magnetic equator and sometimes in the polar and auroral regions. Most scintillation occurs for a few hours after sunset during the peak years of the solar cycle. This paper focuses on estimation of the effects of ionospheric scintillation on GPS and SBAS signals using a software receiver. Software receivers have the advantage of flexibility over conventional receivers in examining performance. PC based receivers are especially effective in studying errors such as multipath and ionospheric scintillation. This is because it is possible to analyze IF signal data stored in host PC by the various processing algorithms. A L1 C/A software GPS receiver was developed consisting of a RF front-end module and a signal processing program on the PC. The RF front-end module consists of a down converter and a general purpose device for acquiring data. The signal processing program written in MATLAB implements signal acquisition, tracking, and pseudorange measurements. The receiver achieves standalone positioning with accuracy between 5 and 10 meters in 2drms. Typical phase locked loop (PLL) designs of GPS/SBAS receivers enable them to handle moderate amounts of scintillation. So the effects of ionospheric scintillation was estimated on the performance of GPS L1 C/A and SBAS receivers in terms of degradation of PLL accuracy considering the effect of various noise sources such as thermal noise jitter, ionospheric phase jitter and dynamic stress error.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.17-22
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• 2009

A switch or circulator is used for distinguishing between the paths of transmitter and receiver in TDD systems. If the isolation between Tx and Rx paths is low in TDD systems, the output signal of the ransmitter acts as an interferer to the receiver even if the transceiver operates on the receiver mode. In this paper we propose a method to get high isolation characteristics between transmitting and receiving paths in TDD systems. We implement the module with a proposed improving method to verify the effect of the isolation improvement and the experimental results are presented. The isolation improvement of above 44.8 dB over the frequency bandwidth of 30 MHz is obtained from the implemented isolation improvement module.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4B
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• pp.237-244
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• 2003

This paper presents the design of a QPSK/16-QAM downstreams receiver chip. The proposed chip consists of a blind equalizer, a timing recovery block and a carrier recovery block. The blind equalizer uses a DFE sturucture using CMA(Constant Module Algorithm). The symbol timing recovery uses the modified parabolic interpolator. The decision-directed carrier recovery is used to remove the carrier frequency offset, phase offset and phase jitter. The implemented LMDS receiver can support four data rates, 10, 20, 30 and 40 Mbps and can accommodate the symbol rate up to 10 Mbaud. This symbol rate is faster than existing QAM receivers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.163-168
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• 2018

We developed W-band transceiver module using open MMIC chip such as receiver single chip and transmitting power amplifier. In order to calculate the noise figure and output power value, we analyzed the W-band transition loss from the antenna to MMIC connection and constructed the 12 channel receiver and the 5 channel transmitter. And compared with the results of the measurement. As a result, the output power of the transmitter was similar to the analytical results and the measured results at room temperature and environmental conditions. The noise figure of the receiver was also similar, but some channels showed error of about 3 dB due to manufacturing error.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.120-125
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• 2012

Daegu Solar Power Tower Plant of a 200 kW thermal capacity uses an open air receiver. An air receiver is generally based on the volumetric receiver concept with porous ceramic absorbers. Because absorber material is important in the volumetric receiver, ceramic materials with excellent thermal conductivity, high solar absorptivity and good thermal stability have been researched. KIER also developed SiC honeycomb absorber modules and evaluated performance of the modules at the KIER solar furnace. For performance evaluation, we made an open volumetric receiver containing the modules and measured the outlet temperature and the efficiency. It is demonstrated that performance of the KIER absorber is comparable to that of a reference absorber developed by DLR.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.149-157
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• 2014

This paper considers the ability of counting and positioning multi-targets by using a mobile UWB radar device. After a background subtraction process, distinguishing between clutters and human body signals, the position of targets will be computed using weighted Gaussian mixture methods. While computer vision offers many advantages, it has limited performance in poor visibility conditions (e.g., at night, haze, fog or smoke). UWB radar can provide a complementary technology for detecting and tracking humans, particularly in poor visibility or through-wall conditions. As we know, for 2D measurement, one method is the use of at least two receiver antennas. Another method is the use of one mobile radar receiver. This paper tried to investigate the position detection of the stationary human body using the movement of one UWB radar module.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.1
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• pp.110-115
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• 2000

A K-band GaAs MMIC receiver module has been developed using 0.15 ${\mu}{\textrm}{m}$ HEMT technology process. It incorporates two front end low noise amplifiers, a double balanced diode mixer, and filters. The RF input frequency ranges 20.1 to 21 GHz and the IF output 1.1 to 2 GHz. Test results show an overall conversion gain of more than 27 dB, and less than a 2.2 dB noise figure. The image-rejection ratio greater than 21 dB has been obtained. The isolation between RF and IF ports is better than 27 dB, and between LO and IF is more than 50 dB.