Physics 1F- Data Transmission

Physics 1F- Data Transmission

1. Infra-red signals

   • Used in many commonplace devices
     • Remotes
       • Uses digital codes to control different functions of the TV
       • Each function has a different code
         • Sent by a series of flashes
     • Sensors controlling automatic doors
     • Short-distance wireless data links for computers or mobile phones
     • Burglar Alarms (by detecting body heat)
     • Security Lights (by detecting body heat)

2. Analogue

   • Vary continuously in amplitude
   • Can have any value within a fixed range of values
   • Very similar to the sound of speech or music
   • Suffers from interference in the form of noise

3. Digital

   • Transmit data as a series of pulses
   • Don't have vary amplitudes
   • There is states 1 and 0 (on and off)
   • Two or more digital signals can be sent down the same optical fibre at the same time
     • Enabling more information to be sent in one go
     • Known as multiplexing
   • Although suffering from interference known as noise, it doesn't affect the signals because they are still only on or off

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