The document discusses physical layer data transmission and signals. It covers topics like analog vs digital signals, periodic vs non-periodic signals, properties of signals like amplitude, frequency, period, phase, and bandwidth. It also discusses signal representation and analysis in the time and frequency domains, including Fourier analysis which shows how composite signals can be decomposed into simpler sine waves.

1. Link Layer & Physical Layer CPE 400 / 600 Computer Communication Networks Lecture 24

17. IP-Over-ATM DataLink Layer IP datagrams into ATM AAL5 PDUs IP addresses to ATM addresses AAL ATM phy phy Eth IP ATM phy ATM phy app transport IP AAL ATM phy app transport IP Eth phy

20. MPLS forwarding tables DataLink Layer R1 R2 D R3 R4 R5 0 1 0 0 A R6 1 0 in out out label label dest interface 6 - A 0 in out out label label dest interface 10 6 A 1 12 9 D 0 in out out label label dest interface 8 6 A 0 in out out label label dest interface 10 A 0 12 D 0 8 A 1

23. TCP/IP and OSI model

24. Source-to-destination delivery

25. Physical layer Physical Layer To be transmitted, data must be transformed to electromagnetic signals.

26. Physical Layer Chapter 3: Data and Signals Chapter 4: Digital Transmission Chapter 5: Analog Transmission

28. Comparison of analog and digital signals Physical Layer

30. Signal amplitude Physical Layer

32. Frequency and period are the inverse of each other. Units of period and frequency Frequency and Period Physical Layer

33. Two signals with the same amplitude, but different frequencies Physical Layer

34. The power we use at home has a frequency of 60 Hz . What is the period of this sine wave ? Examples The period of a signal is 100 ms. What is its frequency in kilohertz? Physical Layer

35. Phase describes the position of the waveform relative to time 0 Phase Three sine waves with the same amplitude and frequency, but different phases Physical Layer

36. A sine wave is offset 1/6 cycle with respect to time 0. What is its phase in degrees and radians? Example Solution We know that 1 complete cycle is 360°. Therefore, 1/6 cycle is Physical Layer

37. Wavelength and period Physical Layer Wavelength = Propagation speed x Period = Propagation speed / Frequency

38. Time-domain and frequency-domain plots of a sine wave Physical Layer A complete sine wave in the time domain can be represented by one single spike in the frequency domain.

41. A composite periodic signal Decomposition of the composite periodic signal in the time and frequency domains Physical Layer

43. The bandwidth of a composite signal is the difference between the highest and the lowest frequencies contained in that signal. Bandwidth Physical Layer

44. A nonperiodic composite signal has a bandwidth of 200 kHz, with a middle frequency of 140 kHz and peak amplitude of 20 V. The two extreme frequencies have an amplitude of 0. Draw the frequency domain of the signal. Solution The lowest frequency must be at 40 kHz and the highest at 240 kHz. Example Physical Layer