SIGNALLING - Digitising a Signal Flashcards
What does a signal do?
Transfers information from one place to another and can be conveyed through sound or light.
Name two examples of signals.
A red traffic light, a stream of binary highs and lows, (1s and 0s)
How are signals digitised?
Information is coded into a string of binary digits which are transmitted through air, space, wires, or optical fibres, from the sender to the receiver.
How do emails use digital signals?
Emails use digital signals. Each character is sent as a 1 byte number code.
When were analogue signals used and what for?
Analogue signals vary continuously. Their sound vibrations in analogue telephones would be changed to represent oscillations of PD and analogue was used for most long distance communications in the 20th century.
What happens when analogue signals are amplified?
When analogue signals became distorted or noisy, they had to be amplified when weaker, and this would boost the signal and noise. Turning up a badly tuned radio with hiss would amplify the hiss.
What’s noise?
Random variation on the signal.
What are benefits to digital signals with regard to transmission and noise?
Noise can be filtered out but detail is lost as a result. In digital systems with a weaker signal, it’s easier to detect binary on/off signals and perfect copies can be regenerated. Digital signals transmit faster too.
