1、通訊原理 2. 數位通訊理論,國立中正大學通訊工程學系劉宗憲助理教授,通訊的內涵與目的,通訊的原意是指意見的溝通或訊息的交換。但現代的通訊還包括了以無線或有線方式，將聲音、影像與文字等多媒體訊息傳輸至遠端的意思。從技術層面來定義，則是指將各種訊號經編碼與調變處理後，仍能有效率、安全且成功地傳送至遠方，其間即使有各種吵雜、干擾也不受影響。,通訊技術的演變歷史,通訊技術的演變 (continued),1G,2G,3G,2.5G,AMPS,ETACS,D-AMPS,GSM,PDC,IS-95A,IS-95B,GPRS,UWC-136,WCDMA,cdma2000,TD-SCDMA,Evolution
2、 of Cellular Mobile Communications,Phase 1,Phase 2,Phase 1,Phase 2+,Phase 2,Phase 1,Capabilities,Year,1991,1995,1997,Downward Compatibility,IMT-2000,UMTS,W-CDMA,etc.,GSM Evolutionary Concept,Selected Radio Frequency Bands,The most precious resource in communications is “frequency spectrum”The “frequ
3、ency spectrum” has to be shared by a large number of users and applications:AM Radio, FM Radio, TV, cellular telephony, wireless local-area-networks, satellite, air traffic control,Frequency Spectrum,Transmit Spectrum,Allocated Channels,Internal and External NoiseInternal Noise: Generated by components within a communication system (thermal noise)External Noise: Atmospheric noise (electrical discharges)Man-made noise (ignition noise)Interference (multiple transmission paths),Noise,t1,t2,t3,通道效應Multipath Fading,通訊的基本功能單元,Analog Vs Digital (Advantages and Disadvantages),
