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1.1 Introduction
1 Jimes C.Maxwell（1864） 2 Heinrich Hertz （1887） 3 Claude E.Shannon (1948) 4.Winner
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1.1 Introduction
Perspective of communication Wire
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1.1 Introduction
What is a communication system? Communication systems is used to transmit information.
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1.1 Introduction
Key conceptions or words (1) Information; (2) Message; (3) Signal; (4) Waveforms
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Receiver
The receiver takes the corrupted signal at the channel output and converts it to a baseband
signal that can be handled by the receiver baseband processor, and then the receiver
现代通信原理课件Chapter One
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Chapter One
Introduction
Why? Information Age Information Superhighway
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Chapter One Application
military application; common application;
2)Function of signal-processing block in hybrid one Source coding Channel coding(adding parity and others)
3) Function of Carrier Circuits modulation
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1. Selection of the information-bearing
waveform
2. Bandwidth and power of the
waveform

3. Effect of system noise on the received
information
4. Cost of the system
2) Note: The general principles of digital and analog modulation apply to all types of channels, although channel characteristics may impose constraints that favor a particular type of signaling
optic-fiber and networks wireless
1G->2G->3G->B3G WLAN; MIMO and MIMO-OFDM, UWB, optic –wireless communication
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1.1 Introduction
What must be considered when you design a communication system?
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1.2 Digital and Analog source and system
• The generation of communication system
Information input m(t)
Signal processing
Carrier circuits
Transmitter
channel noise
baseband processor estimate the source information and output the estimation result
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Summary
The goal is to design communication system that transmit information to the receiver with as little deterioration as possible while satisfying design constrains such as allowable transmitted energy,allowable signal bandwidth and cost. In digital system measure of deterioration is taken to be bit error rate(BER),while in analog system the performance measure is usually taken to be the signal-to-noise ratio(SNR) at the receiver output.
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1.2 Digital and Analog source and system
Channel
1） Classification: wire and wireless
Wire channel including twisted-pair telephone line/Coaxial cables,waveguides and fiber-optic cables
Wireless channel having air,vacuum and seawater
Information output
Signal processing
Carrier circuits
Receiver
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Function of transmitter
1) signal processor In analog system it may be an analog lowpass filter; In hybrid one, it may be analogto-digital converter(ADC)