【正文】 a mon digital transmission system 2 the advantage of digital system Digital and Analog source and system 17 5） Noise does not accumulate in long distance systems by repeater 6） Error in detected data may be small, even in large amount of noise on the received signal 7） Error may often be corrected by the use of coding 2 the advantage of digital system Digital and Analog source and system 18 1)More bandwidth is required generally 2)Sychronization is required of Digital munication Digital and Analog source and system 19 Digital and Analog source and system (classification of munication system) according to physical properties of information : Telephone /data /image and so on according to frequency : baseband transmitting/ bandpass transmitting system according to transmitting medium : wire /wireless according to multiplexing patterm: Frequency division multiplexing access(FDMA) Time division multiplexing access(TDMS) Code division multiplexing access(CDMA) 20 Digital and Analog source and system ? Classification of munication patterm ? Peer to peer munication : simplex。 half duplex。 MIMO and MIMOOFDM, UWB, optic –wireless munication Introduction 8 What must be considered when you design a munication system? 1. Selection of the informationbearing waveform 2. Bandwidth and power of the waveform 3. Effect of system noise on the received information 4. Cost of the system Introduction 9 Digital and Analog source and system ? The generation of munication system T r a n s m i t t e r I n f o r m a t i o n i n p u t m ( t ) S i g n a l p r o c e s s i n g c h a n n e l S i g n a l p r o c e s s i n g C a r r i e r c i r c u i t s R e c e i v e r n o i s e C a r r i e r c i r c u i t s I n f o r m a t i o n o u t p u t 來自 10 1) signal processor In analog