• 전기의세계
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• v.43 no.12
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• pp.46-54
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• 1994

본 문에서는 최근 여러방면에서 주목받고 있는 대역확산통신방식에 대해 살펴본다. 대역확산통신의 원리를 살펴보고, 대역확산통신의 여러가지 방식의 기본개념과 특징에 대해 알아본다. 또한 대역확산통신방식을 이용한 각종 응용에 대해 고찰해 본다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.350-351
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• 2012

본 논문에서는 ATSC 지상파 DTV시스템에서 계층변조를 사용하여 재난 방송용 부가 데이터를 전송하는 기법을 제안한다. ATSC 지상파 DTV시스템에서 계층변조를 사용하는 방식으로는 ADT(Augmented Data Transmission) 방식과 대역확산방식이 있다. ADT방식은 상대적으로 높은 데이터 전송율을 가지지만 신호가 도달할 수 있는 커버리지가 좁은 반면 대역확산방식은 낮은 데이터 전송률을 가지지만 신호가 도달할 수 있는 커버리지가 넓은 장점이 있다. 따라서, 재난 발생시 넓은 커버리지에 신속하게 긴급경보 방송을 송신하기 위해서는 대역확산기반의 계층변조 방식이 유리하다. 본 논문에서는 ATSC 지상파 DTV시스템에서 긴급경보 방송을 위해 대역확산기반의 계층변조 방식을 사용한 경우 전송용량 및 전계강도와 도달할 수 있는 전송 거리를 분석한다.

• Aerospace Engineering and Technology
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• v.10 no.1
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• pp.45-53
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• 2011

This paper is technical review about Direct Sequence Spread Spectrum(DSSS) to apply in launch vehicle system. First, we introduce communication protocol(carrier frequency, code length, process gain, data rate, chip rate etc) about several application system using DSSS. And then, we survey and summarize the effect of doppler shift to the DSSS. The doppler shift is important error factor for PN code tracking in the fast moving system like launch vehicle. So, spread spectrum code acquisition technique for a direct sequence system in the presence of doppler effect must be investigated.

• Information and Communications Magazine
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• v.2
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• pp.91-100
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• 1985

본 소고에는 PN부호와 대역확산통신의 기본적인 관계를 설명하고 PN부호가 대역확산통신에 어떻게 사용하는가를 상술한다. 먼저 PN부호의 발생방법과 PN부호가 가지고 있는 특성을 설명하고 PN부호를 가지고 주파수도약을 위해 주파수합성기를 어떻게 구성하는가를 설명한다. 끝으로 간단한 대역확산통신방식과 PN부호 관계를 연결지어 논하기로 한다.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.35C no.10
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• pp.12-21
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• 1998

A chaotic spread spectrum communication system using a polar quarternary method is designed and implemented. Four different chaotic signals in the relation of multiplication each other are generated through the use of a coupled synchronization method in the transmitter which is composed of four Chua's circuits. Information is retrieved at the receiver which is connected to the transmitter through the use of a drive synchronization method. Since spread spectrum of information signal is spread by chaotic signal, the configuration of the system is simpler than that of any other conventional system.

• Aerospace Engineering and Technology
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• v.8 no.1
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• pp.179-186
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• 2009

This paper describes the design and implementation for spread spectrum FTS encoder and decoder. The FTS command format is defined by 64 bit encrypted packet that contains all required information relayed between the ground and the vehicle. Encryption is accomplished using the Tripple-DES encryption algorithm in block encryption form. The proposed FTS encoder and decoder is using the Convolution Encoding and Viterbi Decoding for forward error correction. The Spread Spectrum Modulation is done using a PN code, which is 256 bit gold code. The simulation result shows that the designed FTS decoder is compatible with the designed FTS encoder.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.250-252
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• 2003

본 논문에서는 콘벌루션 부호를 사용한 대역확산 방식의 디지틀 통신모뎀을 FPGA를 이용하여 설계 및 검증을 하였다. 대역확산 방식에서의 콘벌루tus부호기(K=3, R=1/2), PN code(128chip) generator와 비터비 디코더를 Xilinx사의 FPGA 디자인 툴인 Xilinx Foundations3.1을 사용하여 VHDL simulation과 timing simulation을 수행하였고, FPGA 회로설계 검증 장비인 EDA-Lab 3000 장비를 사용하여 Xilinx사의 SPARTAN2 2S100PQ208칩에 configuration 한 후 Agilent사의 1681A logic analyzer를 사용하여 설계된 회로의 동작을 검증하였다.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.1
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• pp.24-36
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• 2002

It is important to use frequency resource effectively to support much more users, to maximize the DS-CDMA system performance. In this paper, we use MPSK, QAM, MFSK and PR coder as a baseband modulation method for DS-CDMA system. Increasing user's number, we compare the performance of each system using different baseband modulation method, by expecting BER performance. BPSK has generally good performance, in case of low power operation of terminal 8FSK has excellent performance relatively, PR has excellent performance when high power operation of terminal and also good for situation of excessive user's number. QAM is not suitable for DS-CDMA system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.8
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• pp.1629-1637
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• 2003

In this paper, we analyzed the performance of a hybird DS/SFH(Direct­Sequency­Slow Frequency­Hopping) Spread Spectrum system with BFSK modulation over Nakagami­m fading channel with multitone jamming. The performance of the system was improved when a frequency bowing rate increased. In case that process gain of hybrid DS/SFH Spread Spectrum system to be fixed, the hybrid DS/SFH Spread Spectrum takes the low bit error probability than a DS Spread Spectrum system. Also, when the fading index m increases, the fading effect decrease, when the JSR(jamming to signal power ratio) increases ,the performance of a hybrid DS/SFH Spread Spectrum system improved than DS Spread Spectrum system. The result, we have been proved that performance of a hybrid DS/SFH Spread Spectrum was superior to DS Spend Spectrum system over Nakagami­m fading with tome jamming.

• The Journal of the Acoustical Society of Korea
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• v.40 no.4
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• pp.304-313
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• 2021

This paper presents the results of a sea trial for long range underwater acoustic communication conducted in the East Sea in November 2020. Signals were collected through a moving transmitter and 16 vertically arranged receivers, and the range between the transmitter and receiver was about 20 km. The signal in the experiment is a conventional Direct Sequence Spread Spectrum (DSSS) method and a superimposed DSSS method that increases data rate by superimposing of multiple circulated Pseudo Noise (PN) sequences for each symbol. The results show that the uncoded bit error rate averaged over 16 channels to which the channel coding technique was not applied was 0.0005 for the conventional direct sequence spreading method, and was 0.00124 for the superimposed direct sequence spreading method.