Data and Computer Communications

Data and Computer Communications

1. Transmission Terminology

   • data transmission occurs between a transmitter & receiver
   • guided medium
   • unguided / wireless medium
   • simplex
   • half duplex
   • full duplex
   • direct link
   • point-to-point
   • multi-point

2. Frequency, Spectrum and Bandwidth

   • time domain concepts
     • digital signal
     • analog signal
     • periodic signal
     • aperiodic signal

3. Sine Wave

   • peak amplitude (A)
   • frequency (f)
   • phase ()

4. Wavelength ()

   • is distance occupied by one cycle

5. Frequency Domain Concepts

   • signal are made up of many frequencies

6. Spectrum & Bandwidth

   • spectrum
   • absolute bandwidth
   • effective bandwidth
   • DC Component

7. Data Rate and Bandwidth

   • any transmission system has a limited band of frequencies

8. Analog and Digital Data Transmission

   • data
   • signals & signalling
   • transmission

9. Audio Signals

10. Video Signals

11. Analog Signals

12. Digital Signals

13. Advantages & Disadvantages of Digital Signals

    • cheaper
    • less susceptible to noise
    • but greater attenuation
    • digital now preferred choice

14. Transmission Impairments

    • Attenuation
    • Delay Distortion
    • Noise

15. Channel Capacity

    • max possible data rate on comms channel
      • function
        • data rate - in bits per second
        • bandwidth - in cycles per second or Hertz
        • noise - on comms link
        • error rate - of corrupted bits