PHYSICAL LAYEROverviewDigital LinkDigital Link (continued)Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Optical LinkOptical Link (continued)Slide 14Slide 15Slide 16Copper LinkCopper Link (continued)UCBPHYSICAL LAYERJean WalrandU.C. Berkeleywww.eecs.berkeley.edu/~wlrUCBOverviewDigital LinkOpticalCopperWirelessUCBDigital LinkStructure:UCBDigital Link (continued)ExamplesUCBDigital Link (continued)Frequency and Propagation:UCBDigital Link (continued)Limitations:UCBDigital Link (continued)Baseband: Not self-clockingUCBDigital Link (continued)Baseband: Self-ClockingUCBDigital Link (continued)Optical: Self-ClockingB/B or B/0BBasic Idea: Introduce enough transitions so that the signal contains the clock.UCBDigital Link (continued)Broadband: PSK and BPSKUCBDigital Link (continued)Spectrum of BPSK (0 bps, carrier 600 Hz) => 0HzOther modulation schemes: to bps per HzNote: Shannon Capacity is W log( + S/N)UCBOptical LinkComponents:UCBOptical Link (continued)Fibers:UCBOptical Link (continued)AttenuationUCBKey Ideas: • Synchronize Transmitters for easy ADM• Enable slipping between PATH and LineOptical Link (continued)SONETUCBOptical Link (continued)SONET FrameUCBCopper LinkCommon Modulation: QPSKUCBCopper Link (continued)ADSLDMT: • Divides bw into channels of kHz• Uses QAM in each channel, based on
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