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The physical layer

The physical layer. Skills : none IT concepts : wired physical media characteristics, wireless physical media characteristics (power and frequency), modulation schemes. This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License. Internet concepts

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The physical layer

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  1. The physical layer Skills: none IT concepts: wired physical media characteristics, wireless physical media characteristics (power and frequency), modulation schemes This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

  2. Internet concepts Applications Technology (communication) Implications for Internet skills Application development Content creation Where does this topic fit?

  3. TCP/IP protocol layers from 1,000 feet up Programs that do useful work like retrieve Web pages, copy files, send and receive email, etc. Make client-server connections and optionally control transmission speed, check for errors, etc. Route data between networks Route data within the local area network Specify what medium connects two nodes, how binary ones and zeros are differentiated, etc.

  4. Physical characteristics of wired media

  5. Physical characteristics of wireless media Frequencies and channels Power

  6. 15-20 Mbps 20-22 Mbps 10-15 Mbps 5-10 Mbps Coverage 802.11g WiFi access point, < 1 watt 200 feet 125 feet

  7. Estimated coverage for 600 watt KPCC Irregularity due to varying terrain Radio locator

  8. Coverage, southwest US, 250,000 watt XERF Wolfman Jack

  9. Frequency KPCC FCC frequency allocation, zip code 90747 Central carrier frequency, for example 89.3 mHz for KPCC

  10. AM and FM modulation Signal AM FM Animation

  11. Modulation schemes or

  12. Paul Revere’s one-bit message By land (0) By sea (1)

  13. More old ways to transmit ones and zeros Electric

  14. Morse code Dot = 0 Dash = 1

  15. Radio

  16. Modulation – transmit ones and zeros The transmitter can generate these differences and the receiver can detect them.

  17. A more sensitive receiver – 4 levels, not 2

  18. Other types of wave with geek terms

  19. Claude Chappe’s semaphore, 1792

  20. The operator used two cranks to move the arms.

  21. Early 1800s

  22. The physical layer Skills: none IT concepts: wired physical media characteristics, wireless physical media characteristics (power and frequency), modulation schemes This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 License.

  23. A few questions If an AM transmitter and receiver can differentiate between four different amplitudes, how many bits are transmitted in each carrier clock period? If an FM transmitter and receiver can differentiate between 8 different frequencies, how many bits are transmitted in each carrier clock period?

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