Digital Transmission (Line Coding)（数字传输(代码行)）.pdf

Digital Transmission (Line Coding)(Line Coding) EE4367 Telecom. Switching Transmission Prof. Murat Torlak Pulse TransmissionPulse Transmission Source Multiplexer Line Coder Line Coding: Output of the multiplexer (TDM) is coded into electrical pulses or waveforms for the purpose of transmission over the channel (baseband transmission) Many possible ways, the simplest line code on-off All digital transmission systems are design around All digital transmission systems are design around some some particular form of pulse response. (a) On-off (RZ) (b) Polar (RZ) (c) Bipolar (RZ) (d) On-Off (NRZ) Nonreturn-to-zero (NRZ) (e) Polar (NRZ) Return-to-zero (RZ) EE4367 Telecom. Switching Transmission Prof. Murat Torlak Pulse Transmission over a ChannelPulse Transmission over a Channel EE4367 Telecom. Switching Transmission Prof. Murat Torlak Desirable Properties for Line Codes Desirable Properties for Line Codes Transmission Bandwidth: as small as possible Power Efficiency: As small as possible for given BW and probability of error Error Detection and Correction capability: Ex: Bipolar Favorable power spectral density: dc=0 Adequate timing content: Extract timing from pulsesAdequate timing content: Extract timing from pulses Transparency: Prevent long strings of 0s or 1s EE4367 Telecom. Switching Transmission Prof. Murat Torlak Review: Energy Review: Energy and Power Signalsand Power Signals An energ