• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.5
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• pp.473-481
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• 1988

In this paper, we investigated bit error probabilities of GMSK, which is known to be one of promising modulation techniques for a digital mobile radio, under various mobile radio environments.: AWGN, slow Rayleigh fading channel, co-channel interference and adjacent channel interference. We employed an MSK-type receiver for a coherent detection and assumed degrading to both signals than adjacent channel interference. Especially, it is found that GMSK suffers more degradations than MSK from the co-channel interference. But with a high power adjacent channel interference, GMSK shows less bit error rate than MSK. The results confirm a higher spectrum efficiency of GMSK.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2623-2626
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• 2003

GPS provides two services which include SPS(Standard Positioning Service) and PPS(Precise Positioning Service). While SPS users can navigate in more precise due to cancellation of SA(Selective Availability), SPS users has still less precision navigation than PPS users. L1/L2CS integrated receiver can provide more precise navigation to SPS users because the delay of Ionosphere will be cancelled by using two frequencies (L1 and L2). This paper designs an integrated L1/L2CS digital correlator to prepare the L2C signal that will be provided in 2003. Also L2CS transmitter is designed to confirm L2CS correlator.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.183-186
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• 2004

The proposed system in this paper utilizes the SIP and self-defined control protocol to provide global wireless communication over the data link of Orbcomm system. Main processor board connected to Orbcomm communication subscriber is designed to interface with digital I/O and AD/DA convertor for various application of control and .measurement. Hardware system implemented in this paper also includes the function of real-time clock and position report using GPS receiver The experimental result of the proposed global wireless communication system is evaluated via real-time experiments, and we have confirmed it works well according to the protocol designed in this paper.

• JSTS:Journal of Semiconductor Technology and Science
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• v.4 no.3
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• pp.210-216
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• 2004

In this paper, we propose a noncoherent On-Off Keying (OOK) Ultra Wide Band (UWB) system based on power detection with noise power calibration for low power applications. The proposed UWB system achieves good bit error rate performance which is favorably comparable to that of the system using the ideal adaptive threshold, while maintaining simple receiver structure, In addition, low power Analog Front-End (AFE) blocks for the proposed noncoherent UWB transceiver are proposed and verified using CMOS technology. Simulation results on the pulse generator, delay time generator and 1-bit Analog-to-Digital (AID) converter show feasibility of the proposed UWB AFE system.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.219-224
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• 2014

In this paper, we study the scattering characteristics of particle using Mie scattering based on various variables such as particle size and refraction of particle, wavelength of laser and angle of receiver to get diffuse light. And we consist a optical system for particle detection, then analyzed the characteristics of the optical system. And based on these characteristics, we develop a particle detection chamber for particle counter and shows experiment result.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.553-555
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• 2004

In this paper, high performance radio buoy system used for inshore and deep sea fishery is developed and experimented. Location of radio buoy can be accurately monitored and traced by the mother ship using GPS technology, and optimum access protocol is adopted to minimize the power consumption of radio buoy system. Developed system can cover over 80Km coastal range with 8 W transmitting power and -115 dBm receiver sensitivity and can ensure high security from burglary and loss using digital coding technology.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.935-938
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• 2001

본 논문에서는 하드디스크를 내장한 디지털 위성방송 수신기의 설계 및 구현에 대해 기술한다. 디지털 방송 기술의 발달로 인해 방대한 양의 디지털 멀티미디어 데이터의 전송과 접근이 가능해졌다. 이러한 방송 데이터를 실시간으로 저장하기 위한 하드디스크 인터페이스와 방송의 저장과 재생 등 기존 아날로그 비디오 레코더가 가지는 기능 외에 하드디스크의 특성을 이용한 랜덤 액세스 기능 등 디지털 비디오 레코더(DVR)의 기능이 포함된 하드디스크 내장 위성방송 수신기를 개발하였다. 이 수신기는 PC에서 사용되는 파일 시스템보다 멀티미디어 데이터에 적합하도록 디스크 클러스터의 크기와 한정된 메모리를 고려하여 설계된 파일 시스템을 이용해 저장된 멀티미디어 데이터를 효과적으로 관리하는 부분을 포함한다. 이러한 시스템을 이용함으로써 방송의 효과적인 시청과 멀티미디어 데이터의 효율적인 관리가 가능해진다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.11b
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• pp.71-75
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• 1999

본 논문은 한국형 디지털 TV 방송 규격/sup [1]/을 따르는 디지털 지상파 방송 신호를 수신할 수 있는 DTV 수신기의 구조에 관한 것이다. 국내 방송은 99년 10월 실험 방송이 시작될 예정이며 현재 제한된 지역에서 일부 방송을 하고 있는 상태다. 본 셋트는 8 VSB로 전송되는 디지털 방송신호를 수신할 수 있으며, ATSC 표준/sup [2]/에서 규정한 18가지 영상 포맷을 디코딩하여 화면에 디스플레이 할 수 있다. 특히 고화질 변환기능을 채용해 디지털 방송 활성화 이전에도 아날로그 TV방송, DVD, VCR 등 프로그램을 고화질로 즐길 수 있다. 또한 본 시스템을 구현하기 위해 자사가 개발한 DTV용 칩 셋을 사용하였다.

• Journal of Sensor Science and Technology
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• v.27 no.3
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• pp.143-149
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• 2018

In this paper, we introduce an edge-spike modulation method for visible light communication (VLC). This method is effective in preventing LED flicker and 120 Hz noise interference in base-band VLC. In the VLC transmitter, edge-spikes are generated by passing the digital data through a simple RC-high pass filter (HPF). The LED modulation of the edge-spikes does not change the average power of the LED light; thus it prevents LED flicker. In the VLC receiver, the 120 Hz noise from other lighting lamps is easily eliminated by RC-HPF, while the edge-spike signal is detected normally. In our experiment, the message of an air-quality sensor was successfully transmitted using edge-spike modulation. This structure is useful in constructing, e.g., wireless gas monitoring sensor systems to warn and prevent harmful gas leakage accidents in buildings using LED light.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.11-18
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• 2005

Filament inversion routines are highly effective for target definition whenever total-field DHTEM vectors can be obtained using three-component logging tools. However most cross-hole components contain significant noise related to sensor design and errors in observation of probe rotation. Standard stacking methods can be used to improve data quality but additional statistical methods based on cross-correlation and spatial averaging of orthogonal components may be required to ensure a consistent vector migration path. Apart from assisting with spatial averaging, multiple filaments generated for successive time-windows can provide additional imaging information relating to target geometry and current migration. New digital receiver systems provide additional time-windows to provide better tracking options necessary for high-resolution imaging of this type.