1 multiplexing

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1 multiplexing

  1. 1. Unit -3 MultiplexingWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  2. 2. Figure 8-1 Multiplexing vs. No MultiplexingWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  3. 3. Multiplexing• Enable two or more transmission sources to share a common circuit• Most common forms – FDM and TDM• FDM – associated with analog signal, simultaneous transmission• TDM – associated with digital signal (could also be analog) with time slices 3
  4. 4. Multiplexing 4
  5. 5. Frequency Division Multiplexing• Each signal is modulated to a different carrier frequency• Carrier frequencies separated so signals do not overlap (guard bands)• Channel allocated even if no data 6
  6. 6. Frequency Division Multiplexing Diagram 7
  7. 7. Figure 8-3 FDMWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  8. 8. Figure 8-5 Multiplexing, Frequency DomainWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  9. 9. Figure 8-7 Demultiplexing, Frequency DomainWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  10. 10. Figure 8-4 FDM, Time DomainWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  11. 11. Figure 8-6 Demultiplexing, Time DomainWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  12. 12. TDM
  13. 13. Synchronous Time Division Multiplexing• Multiple digital signals interleaved in time• May interleave bits, so not necessarily synchronous transmission• Time slots pre-assigned to sources and fixed• Time slots allocated even if no data• Time slots do not have to be evenly distributed amongst sources 14
  14. 14. Time Division Multiplexing 15
  15. 15. Figure 8-9 Synchronous TDMWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  16. 16. TDM, Multiplexing
  17. 17. Figure 8-11 TDM, DemultiplexingWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  18. 18. Framing Bits
  19. 19. Figure 8-13 Data RateWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  20. 20. Figure 8-14 Asynchronous TDMWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  21. 21. Figure 8-15 Frames and Addresses a. Only three lines sending dataWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  22. 22. Figure 8-15-continued Frames and Addresses b. Only four lines sending dataWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  23. 23. Figure 8-15-continued Frames and Addresses c. All five lines sending dataWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  24. 24. Wavelength Division Multiplexing• Multiple beams of light at different frequency• Carried by optical fiber• A form of FDM• Each colour of light (wavelength) carries separate data channel 25
  25. 25. WDM Operation• Same general architecture as other FDM• Number of sources generating laser beams at different frequencies• Multiplexer consolidates sources for transmission over single fiber• Optical amplifiers amplify all wavelengths – Typically tens of km apart• Demux separates channels at the destination 26
  26. 26. Figure 8-16 WDM - Wavelength Division MultiplexingWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  27. 27. Figure 8-16 WDM - Wavelength Division MultiplexingWCB/McGraw-Hill © The McGraw-Hill Companies, Inc., 1998
  28. 28. WDM - Wavelength Division Multiplexing

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