GCSE Science/Analogue and digital signals
Signals can be transmitted as either analogue or digital signals.
Digital signals
[edit | edit source]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 | edit source]- 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 | edit source]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.