• Journal of electromagnetic engineering and science
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• 제16권4호
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• pp.241-247
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• 2016

This paper proposes the design and measurement of a 6-18 GHz front-end receiver module that has been combined into a one- channel output from a two-channel input for electronic warfare support measures (ESM) applications. This module includes a limiter, high-pass filter (HPF), power combiner, equalizer and amplifier. This paper focuses on the design aspects of reducing the noise figure (NF) and matching the phase and amplitude. The NF, linear equalizer, power divider, and HPF were considered in the design. A broadband receiver based on a combined configuration used to obtain low NF. We verify that our receiver module improves the noise figure by as much as 0.78 dB over measured data with a maximum of 5.54 dB over a 6-18 GHz bandwidth; the difference value of phase matching is within $7^{\circ}$ between ports.

• 한국전자통신학회논문지
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• 제7권5호
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• pp.975-981
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• 2012

본 논문에서는 다중 경로 채널 환경에서 터보 코드를 사용하여 광대역 CDMA 시스템의 수신 신호를 고려하고, 시스템의 성능을 분석합니다. Rayleigh 페이딩 채널 환경에서 터보 코드와 함께 레이크 수신기를 통해 수신된 신호를 전달하여 레이크 수신기의 가지 수에 따라 가변 시스템 대역폭에 대한 성능을 분석한다. 광대역 CDMA 시스템에서 수신기의 디자인을 위해서는 디코딩 및 레이크 수신기의 가지 수를 효율적인 매개 변수를 제시했습니다.

• 한국경영과학회지
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• 제20권1호
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• pp.35-54
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• 1995

Routing in ATM network is set up by combination of both virtual path routing and virtual channel routing. While virtual channel is similar concept to virtual circuit of data networks, virtual path is a special concept which is not used in traditional data networks. Virtual path can rearrange in structure and size by simply changing virtual path routing tables and giving the network the capability to eash allocate network resources according to the demand needs. This paper provides reconfiguration models of virtual path network which give the bandwidth of link and the routing path for each traffic class. The reconfiguration models are network optimization problems of multicommodity network flow type. The numerical examples are also included.

• 조명전기설비학회논문지
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• 제20권10호
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• pp.158-163
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• 2006

In this paper, we considered the received signal of the wideband CDMA systems using turbo code in the multipath channel environments, and analyze the performance of the system. This study is to analyze the performance for the variable system bandwidth according to the number of branches of rake receiver by passing the received signal through a rake receiver with a turbo code in Rayleigh fading channel environments. For the design of receiver in wideband CDMA systems, we presented the efficient parameters for the number of iterative decoding and the number of branches of rake receiver.

• ETRI Journal
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• 제27권2호
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• pp.223-226
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• 2005

This paper presents the application of a turbo coding technique combined with a bandwidth efficient method known as trellis-coded modulation. A transformation applied to the incoming I-channel and Q-channel symbols allows the use of an off-the-shelf binary/quadrature phase shift keying (B/QPSK) turbo decoder without any modifications. A conventional turbo decoder then operates on transformed symbols to estimate the coded bits. The uncoded bits are decoded based on the estimated coded bits and locations of the received symbols.

• ETRI Journal
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• 제28권4호
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• pp.533-536
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• 2006

A distributed Bragg reflector (DBR) laser and a high speed electroabsorption modulator (EAM) are integrated on the basis of the selective area growth technique. The typical threshold current is 4 to 6 mA, and the side mode suppression ratio is over 40 dB with single mode operation at 1550 nm. The DBR laser exhibits 2.5 to 3.3 mW fiber output power at a laser gain current of 100 mA, and a modulator bias voltage of 0 V. The 3 dB bandwidth is 13 GHz. A 10 Gbps non-return to zero operation with 12 dB extinction ratio is obtained. A four-channel laser array with 100 GHz wavelength spacing was fabricated and its operation at the designed wavelength was confirmed.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.433-437
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• 2000

본 논문에서는 데이터 전송용 특정 소출력 무선국용 무선기기의 송수신단의 회로를 설계하고 제작하여 특성을 측정하였다. 주파수 대역은 424.7~424.95MHz이고, 반이중(Half Duplex Communication) 통신방식, PLL Synthesized, 20 Channel, 12.5kHz Channel Bandwidth 그리고 FSK Modulation/Demodulation 방식을 사용하였다. 송신단은 저잡음 증폭기와 전력증폭기를 사용하여 10mW의 출력으로 설계하였고, 발생되는 스퓨리어스를 감쇄시키기 위해 저역통과필터와 공진 회로로 구성하였다. 수신단은 Dual Conversion 방식을 사용하였다. 설계한 결과, 송신단의 출력은 9.71dBm, 스퓨리어스특성 47dBc 그리고 수신단은 감도가 -113dBm에서 Jitter가 $\pm$12.3%로 나타났다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.245-246
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• 2008

A cell planning and resource allocation scheme called the proposed is presented for improving channel capacity and for maintaining a proper QoS (Quality of Service) over the downlink OFDMA (Orthogonal Frequency Division Multiple Access) system. Through an optimal combination of sectorization and frequency overlay, the proposed scheme accomplishes an improvement in both channel capacity and outage probability. In the simulation, the proposed scheme outperforms 3-sectorization in terms of throughput and outage probability.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.83-84
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• 2008

It is efficient to use the time-domain beamforming to operate the various pulse with the different pulse length, frequency, bandwidth in active sonar system. In this paper, we propose a time-domain beamformer with the cumulative processing in the decomposed channel using the polynomial interpolation to solve the problem of the computational cost, high transmission data rate, and the lack of internal memory.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.305-306
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• 2008

In this paper, we measured the wireless feedback channel near a highway, and analysis results from the measured sample data are described. For characterizing the channel properties, W-CDMA signal of 2GHz frequency, 5MHz bandwidth and 10ms period are used. The scattering function, delay power profile, delay spread, and Doppler spread are measured.