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톤 재밍환경에서 DS-CDMA방식 위성통신 링크의 용량분석
최영균,Choi, Young-Kyun 대한전자공학회 1999 電子工學會論文誌, S Vol.s36 No.6
Jamming is an important factor in the military satellite communication system. In this paper, link capacity and jamming margin of the DS-CDMA(Direct Sequence-Code Division Multiple Access) military satellite communication system are analyzed and calculated under a multitone jamming. The analysis was performed with two types of transponders loaded on a geosynchronous satellite. Calculation methods for link capacity and jamming margin were obtained. The results of the analysis show that capacity of a transponder which does modulation/demodulation, decoding/encoding in addition to despreading/respeading is twice as much as that of a tranponder which does despreading /respreading only. 군 위성통신 체계는 재밍환경을 고려하여 설계되어야 한다. 재밍에 대한 대책으로 위성통신에 직접확산 부호분할 다중접속 방식(DS-CDMA)을 사용시 다중톤 재밍 환경에서 링크용량과 재밍마진을 분석하였다. 위성은 정지궤도에 위치한 위성으로 역확산/재확산방식 중계기를 사용하는 경우와 변복조 및 오류수정까지 하는 경우를 고려하여 각각 링크용량과 재밍마진을 계산하였다. 중계기에서 변복조 및 오류수정까지 하는 경우는 역확산/재확산만 하는 경우보다 용량이 2배이상 증가되는 것으로 나타났다.
티타늄 전극과 전기분해를 이용한 상수 원수의 망간 제거
최영균 ( Young-gyun Choi ),서호영 ( Hoe-yeong Seo ),김성홍 ( Sung-hong Kim ) 조선대학교 공학기술연구원 2020 공학기술논문지 Vol.13 No.1
Manganese causes the black water of tap water. In this study, we investigated the effect of electrolysis for the removal of manganese under various conditions of electrode type, contact time, operating voltage, and catalyst use. The following results were obtained. The manganese removal rate is proportional to the contact time. The difference of manganese removal rate between the titanium electrode and the manganese dioxide coated electrode was not significant. The manganese removal rate was increased as the voltage increase up to 24V. However, it was slightly decreased at 30V. Manganese removal was not increased by electrolysis combined by aeration but the rate was rapidly increased by electrolysis combined with hydrogen peroxide.