GCSE Science/Analogue and digital signals

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Signals can be transmitted as either analogue or digital signals.

Digital signals[edit]

Digital signals are now being increasingly used. They can take only two values:

  • On (1) ___---___
  • Off (0)_________

For instance when a CD is "burned", The information is quite literally burned into it with small holes representing ones and the spaces in between representing zeros (underscores or dashes)

Advantages of digital signals[edit]

  • There is less interference because noise is not recognised and amplified during transmission.
  • Multiple independent signals can easily be transferred over the same physical channel without crosstalk due to multiplexing.

Multiplexing[edit]

In multiplexing, data from multiple signals is split into small sections, optionally compressed, and then sent down a data line. The system cycles though each signal in turn, allowing data from all signals to be transferred over a single data path.