GCSE Science/Analogue and digital signals

Signals can be transmitted as either analogue or digital signals.

Digital signals

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

• 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

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.