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Introduction In natural and man- made signals,there existwidely a special kind of non- stationary signal,forwhich the statistics,correlation function or higher-order statistics,vary not only with time but alsowith multiple incommensurate periods ( periodicallyor polyperiodically) .The random signal,such ascommunication,radar,telemetry,sonar,etc andthe data thatsubjectto seasonal and rhythmic vari-ations,such as hydrologic,oceanic,climatic,ex-hibit periodically the time- varying characteris… 相似文献
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1890年3月6日傍晚,李鸿章在位于天津单街的直隶总督衙门,收到一封来自香港的电报:“丁提督离军时,琅威理应昇何旗?琅稟。”李鸿章不知道他的北洋海军英籍顾问琅威理为何拍来这样一份电报,但一丝不祥之兆掠过了他的心头。他踌躇厂一夜,次日清晨,字斟句酌地起草了一份措辞谨慎的回电,嘱咐立即发往香港,转送北洋海军第二号 相似文献
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