UCB PHYSICAL LAYER Jean Walrand U C Berkeley www eecs berkeley edu wlr UCB Overview Digital Link Optical Copper Wireless UCB Digital Link Structure UCB Digital Link continued Examples UCB Digital Link continued Frequency and Propagation UCB Digital Link continued Limitations UCB Digital Link continued Baseband Not self clocking UCB Digital Link continued Baseband Self Clocking UCB Digital Link continued Optical Self Clocking B B or B 0B Basic Idea Introduce enough transitions so that the signal contains the clock UCB Digital Link continued Broadband PSK and BPSK UCB Digital Link continued Spectrum of BPSK 0 bps carrier 600 Hz 0Hz Other modulation schemes to bps per Hz Note Shannon Capacity is W log UCB Optical Link Components UCB Optical Link Fibers continued UCB Optical Link Attenuation continued UCB Optical Link continued SONET Key Ideas Synchronize Transmitters for easy ADM Enable slipping between PATH and Line UCB Optical Link SONET Frame continued UCB Copper Link Common Modulation QPSK UCB Copper Link continued ADSL DMT Divides bw into channels of kHz Uses QAM in each channel based on SNR
View Full Document
Unlocking...