Data Transmission, Transmission Media and Data EncodingOverviewAnalog vs DigitalFrequency, Period, and PhaseTime Domain vs Frequency DomainData Rate vs BandwidthData vs SignalAttenuation and Dispersion (Delay Distortion)DecibelsChannel CapacityShannon's TheoremTransmission MediaTwisted PairCoaxial CableOptical FiberCoding TerminologyCoding DesignSummaryHomeworkRaj JainThe Ohio State University3-1Data Transmission, Data Transmission, Transmission Media and Transmission Media and Data EncodingData EncodingRaj JainProfessor of CIS The Ohio State University Columbus, OH 43210 [email protected] slides are available on-line at:http://www.cse.ohio-state.edu/~jain/CIS677-00/Raj JainThe Ohio State University3-2OverviewOverviewq Time Domain and Frequency Domainq Decibels q Data vs Signalq Attenuation, Delay Distortion, Noise, Capacityq Physical Media: Twisted pair, coaxial cable, optical fiberq Bit, Hertz, and Baudq Coding Design: Terminology + ConsiderationsRaj JainThe Ohio State University3-3AnalogAnalog vsvs DigitalDigitalAmplitude (volts)(a) ContinuousTimeAmplitude(b) DiscreteTimeRaj JainThe Ohio State University3-4Frequency, Period, and PhaseFrequency, Period, and Phaseq A Sin(2 p πft+ θ)Fig 2.3a+2.4Raj JainThe Ohio State University3-5Time DomainTime Domain vsvs Frequency DomainFrequency DomainFig 2.5+2.6a1.00.50.0Ñ1.0Ñ0.51.00.50.0Ñ1.0Ñ0.51.00.50.0Ñ1.0Ñ0.52.0T0.0 0.5 1.0 1.5(a) sin (2pf1t)2.0T0.0 0.5 1.0 1.5(b) 1/3 sin (2p(3f1)t)2.0T0.0 0.5 1.0 1.5(c) sin (2pf1t) + 1/3 sin (2 p(3f1)t)(f)1.41.21.00.80.60.40.20.0S4f13210(a) s(t) = sin (2pf1t) + 1/3 sin (3(2pf1t))Raj JainThe Ohio State University3-6Data Rate vs BandwidthData Rate vs Bandwidth1.00.50.0ÑÑ0.0 0.5 1.0(a) sin (2pf1t) p( f1)t) p( f1)t)1.5 2.0T1.00.50.0ÑÑ0.0 0.5 1.0(b) sin (2pf1t) p( f1)t) p( f1)t) p( f1)t)1.5 2.0T1.00.50.0ÑÑ0.0 0.5 1.0(c) pf1t)1.5 2.0TFig 2.8Raj JainThe Ohio State University3-7Data Data vsvs SignalSignalTelephoneModemCODECDigital TransmitterAnalogDigitalDataSignalAnalogDigitalAnalogAnalogDigitalDigitalData SignalMediumDataRaj JainThe Ohio State University3-8Attenuation Attenuation and Dispersion (Delay Distortion)and Dispersion (Delay Distortion)DistanceRaj JainThe Ohio State University3-9DecibelsDecibelsq Attenuation = Log10 PinPoutq Example 1: Pin = 10 mW, Pout=5 mW Attenuation = 10 log 10 (10/5) = 10 log 10 2 = 3 dBq Example 2: Pin = 100mW, Pout=1 mW Attenuation = 10 log 10 (100/1) = 10 log 10 100 = 20 dBBelPinPoutdecibelq Attenuation = 10 Log10 VinVoutdecibelq Attenuation = 20 Log10Raj JainThe Ohio State University3-10Channel CapacityChannel Capacityq Capacity = Maximum data rate for a channelq Nyquist Theorem: Bandwidth = W Data rate < 2 Wq Bilevel Encoding: Data rate = 2 × Bandwidth05Vq Multilevel: Data rate = 2 × Bandwidth × log 2 MExample: M=4, Capacity = 4 × BandwidthRaj JainThe Ohio State University3-11Shannon's TheoremShannon's Theoremq Bandwidth = H Hz Signal-to-noise ratio = S/N q Maximum number of bits/sec = H log2 (1+S/N)q Example: Phone wire bandwidth = 3100 HzS/N = 30 dB 10 Log 10 S/N = 30Log 10 S/N = 3S/N = 103 = 1000 Capacity = 3100 log 2 (1+1000) = 30,894 bpsRaj JainThe Ohio State University3-12Transmission MediaTransmission Mediaq Twisted pairq coaxial cableq Optical Fiberq Terestrial Microwaveq Satellite Microwaveq RadioRaj JainThe Ohio State University3-13Twisted PairTwisted Pairq Unshielded Twisted Pair (UTP)q Voice Grade: Telephone wireq Data Grade: Better quality100 Mbps over 50 m possibleq Shielded Twisted Pair (STP)Raj JainThe Ohio State University3-14Coaxial CableCoaxial CableFig 2.20Raj JainThe Ohio State University3-15Optical FiberOptical Fiberq Modes Index =Index of refraction =Speed in Vacuum/ Speed in mediumq Multimodeq Single ModeCladdingCoreCoreCoreCladdingCladdingRaj JainThe Ohio State University3-16Coding TerminologyCoding Terminologyq Signal element: Pulseq Modulation Rate: 1/Duration of the smallest element =Baud rateq Data Rate: Bits per secondq Data Rate = Fn(Bandwidth, signal/noise ratio, encoding)PulseBit+5V0-5V+5V0-5VRaj JainThe Ohio State University3-17Coding DesignCoding Designq Pulse width indeterminate: Clockingq DC, Baseline wanderq No line state informationq No error detection/protectionq No control signalsq High bandwidthq Polarity mix-up  Differential (compare polarity)0 1 0 0 0 1 1 1 0 0 0 0 0ManchesterNRZIClockNRZBits+5V0-5VRaj JainThe Ohio State University3-18SummarySummaryq Time domain vs frequency domainq Data rate vs Bandwidthq Data vs Signal, Analog vs Digitalq Attenuation, Dispersion (delay distortion)q Media: Twisted pair, coaxial, fiberq Coding: Higher data rate, error control, clock syncq NRZ, NRZI, Manchester, MultilevelRaj JainThe Ohio State University3-19HomeworkHomeworkq Read Sections 3.3, 3B (appendix), 4.1, 5.1 of Stallings 6th