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  1. Agenda 1. QUIZ 2. HOMEWORK LAST CLASS 3. HOMEWORK NEXT CLASS 4. FREQUENCIES & PHYSICAL LAYER 5. NOISE 6. TRANSISSION LINES 7. FIBER 8. MICROWAVE 9. SATELLITES & EXAMPLES INTELSAT INMARSAT

  2. Homework Chapter 7: 5, 6, 8, 11, 12, 16, 19, 23, 81, 85 Note: Since the substitute lecturer covered Juniper rather than the class viewgraphs, I’ll cover multiplexing (in syllabus as Session 4) and Error Detection (in syllabus as Session 5) next week.

  3. Homework Chap 2

  4. Physical Layer Wire, Fiber & Wireless

  5. Figure 7-2 Classes of Transmission Media

  6. Figure 7-3 Categories of Guided Media UTP

  7. Figure 7-4 Frequency Range for Twisted-Pair Cable Limitation is distance. Why?

  8. Transmission Lines We understand transmission lines by oversimplifying them: a. Lump all resistances into a single large resistance. What is R? b. Lump all inductances into a single large inductance. What is L? c. Lump all capacitances into a single large capacitance. What is C? d. Lump all conductance (leakage) into a single large conductance. e. Assume perfectly uniform construction and perfect symmetry so it looks exactly the same from both ends. f. Lump all of the above into a simple impedance network and assume stability. What is Zo?

  9. Transmission Lines

  10. Transmission Lines Impedance mismatches (impedance of load does not equal impedance of the line) result in a standing wave ratio (how much energy is reflected back to the transmitter).

  11. Figure 7-5 Twisted-Pair Cable

  12. Figure 7-6 Effect of Noise on Parallel Lines

  13. Figure 7-7 Effect of Noise on Twisted-Pair Lines

  14. Figure 7-8 Cable with Five Unshielded Twisted Pairs of Wires

  15. Figure 7-9 UTP Connection

  16. Figure 7-10 Shielded Twisted-Pair Cable Helps eliminate cross-talk. What is cross-talk?

  17. EIA Categories of UTP • Category 1. The basic twisted-pair cabling used in telephone system. OK for voice & low speed data. • Category 2. Next higher grade. Generally good for voice & data up to 4 Mbps. • Category 3. Required to have at least 3 twists per foot and can be used for data transmission up to 10 Mbps. Standard for most telephone systems. • Category 4. At least 3 twists per foot & other conditioning to bring transmission rate up to 16 Mbps. • Category 5. Used for data transmission up to 100 Mbps.

  18. Figure 7-11 Frequency Range of Coaxial Cable Why this lower limit?

  19. Figure 7-12 Coaxial Cable RG 8, 9 & ll. Used in thick Ethernet RG 58. Used in thin Ethernet RG 59. Used for TV

  20. Transmission Line Connector Distortion(Why you need BNC or a good screw) Normal Power Level: - 120 dBm Problem Power Level +/- 10 dB Linear Non-Linear

  21. Fiber Optic Cable Fiber Cable Changes the Game

  22. Figure 7-13 Refraction

  23. Figure 7-14 Critical Angle

  24. Figure 7-15 Reflection

  25. Figure 7-16 Propagation Modes

  26. Figure 7-19 Single-Mode Fiber

  27. Figure 7-20 Fiber Construction

  28. Fiber Optics Attenuation: Light loss due to both scattering and absorption. Absorption: The amount of light loss due to its conversion to heat. Scattering: The disappearance of light due to its leaving the core of of a fiber. Chromatic dispersion: The tendency of a fiber to cause slightly differing wavelengths of emitted light to travel through the fiber at different speeds. (See Handout)

  29. Fiber Optics--Markets Type Environment Type Fiber Common Problem Enterprise Building or campus Multi-mode Dirty patch cord Network Corroded Connector Cable New Installation Single-mode Certification of Contractor Multi-mode Installation Long haul Underground/sea Single-mode Breaks & splices Providers Conduit

  30. Optical Power Budget 0 -5 -10 -15 -20 -25 -30 -35 Launch Power +2dB +2dB -3dB -3dB -2dB -4dB/k +1dB +1dB -3dB By this point you could be down to minus 20 dB By this point you could be down to minus 30 dB Launch Temp Coupling Aging Path Fiber Temp Coupling Repair, Srvce Power to Fiber Loss Loss Effect to Rx Safety Margin Source variables Connector & cable variables

  31. Surface Emitting LEDs, Edge Emitting LEDs & Lasers Attenuation Without Chromatic Dispersion Wavelength in micrometers .85 1.3 1.55 Attenuation -limited MMF MMF SMF MMF SMF span, km SLED 12 30 22 37 30 ELED 14 37 49 46 70 Laser 20 54 104 69 153 Attenuation With Chromatic Dispersion Wavelength in micrometers .85 1.3 1.55 Attenuation -limited MMF MMF SMF MMF SMF span, km SLED 3 24 19 5 4 ELED 5 34 48 9 8 Laser 20 50 104 57 138

  32. Figure 7-21 Radio Communication Band

  33. Figure 7-22 Types of Propagation

  34. Figure 7-23 Frequency Range for VLF

  35. Figure 7-24 Frequency Range for LF

  36. Figure 7-25 Frequency Range for MF

  37. Figure 7-26 Frequency Range for HF

  38. Figure 7-27 Frequency Range for VHF

  39. Figure 7-28 Frequency Range for UHF

  40. Figure 7-29 Frequency Range for SHF C-band: Roughly 4 - 6 GHz Ku-band: Roughly 10 -14 GHz Ka-band: Roughly 20 - 30 GHz

  41. Figure 7-30 Frequency Range for EHF

  42. Figure 7-31 Terrestrial Microwave

  43. Figure 7-32 Parabolic Dish Antenna

  44. Figure 7-34 Satellite Communication

  45. Frequency & Wavelength Increasing Wavelength DecreasingFrequency 30 Khz 300 KHz 3 KHz 3 MHz 10 Kilometers AM Radio---- 30 MHz Radio Frequency Spectrum 1 Kilometer 300 MHz ----Football Field TV & FM Radio---- 100 Meters 3 GHz 10 Meters ----Adult Human 30 GHz 1 Meter Microwaves---- ----Key Chain 300 GHz 10 Centimeters 1 Centimeter 3 THz 1 Milimeter ----Grains of Sand 30 THz Infrared Light---- 100 Micrometers ---Bacteria 300 THz 10 Micrometers 3 PHz Visible Light---- 1 Micrometer 30 PHz 100 Nanometers 300 PHz Ultraviolet Light---- ---Viruses 10 Nanometers 3 EHz 1 Nanometer 30 EHz X-Rays---- 100 Picometers Hz = Hertz K = kilo = 103 M = mega = 106 G = giga = 109 T = tera = 1012 P = peta = 1015 E = exa = 1018 ---Atoms kilo = 103 centa = 10-2 mila = 10-3 micro = 10-6 nano = 10-9 pico = 10-12 10 Picometers IncreasingFrequency Decreasing Wavelength

  46. Figure 7-35 Satellite in Geosynchronous Orbit

  47. Earth Synchronous Orbits and Patterns at Subsatellite Point Polar Ground Trace Satellite Inclined I Inclined i Polar Stationary Equatorial Plane 0 0 Stationary- equatorial i Inclined orbits I,i I

  48. Geostationary Equatorial Orbit wearth wsatellite wearth= wsatellite

  49. Nominal Limits for Geosynchronous Orbit Daily Figure-8 Motion of Geosynchronous Satellite Mean circumference = 264,654 km Nominal Radius (from center of earth) 42,162 km Nominal Height (from surface of earth) 35,786 km Inclination Variation: (for ± 10 0, ± 7,352 km) Apogee-Perigee 85 km typical Active Satellite Box Typical Station-Keeping Volume = 1.62 x 1017 m3 N Latitudinal Motion (N/S) Orbit Motion Direction and Rotation Rate Match Earth’s E W Longitudinal Motion (E/W) Equatorial Plane S

  50. Stationkeeping Window • Perturbations cause “Stationary” satellite to drift from • designated orbital slot • Causes varying roundtrip time (@ ± 285 ms) • Onboard propellant used to maintain position • Fixed and broadcast service satellites positioned to ± 0.050 75 km Earth 85 km 75 km 0.10 Satellite Drift NS EW Orbit Eccentricity 0.001 Equator ± 0.050 Nominal Geostationary satellite orbit