Analogue & Digital Data (Cambridge (CIE) IGCSE ICT)
Revision Note
Analogue & Digital Data
What is analogue data?
Analogue data is continuous data created from non-digital devices
Analogue data can change gradually and smoothly
Examples of analogue data include:
sound waves produced when you talk
data collected by sensors (output)
What is digital data?
Digital data is data represented in a binary format (1s and 0s)
Digital data is created and/or stored using digital devices
Examples of digital data include:
software
documents/files
Characteristics of analogue & digital data
Analogue | Digital |
---|---|
Values change smoothly and gradually | Values are limited (1s and 0s) |
Quality can be lost during storage/transmission | Quality is maintained during storage/transmission |
Needs to be converted to digital to be used in digital devices | Needs to be converted to analogue to use in analogue devices |
Easily manipulated |
Analogue to digital conversion (ADC)
Analogue data must be converted to digital data so that it can be processed by a computer
The ADC process involves taking samples (measurements) of the analogue signal and converting it to a binary code
The sample rate and a higher number of binary digits used in the conversion leads to a more accurate representation of the original signal, but, takes up more space on secondary storage
Digital to analogue conversion (DAC)
Digital data must be converted to analogue data so that it can be used to control devices
The DAC process involves converting discrete digital values (1s and 0s) back into a continuous analogue signal
The quality of the analogue signal after conversion is based on the original sample rate and number of bits used in the digital data
Worked Example
A greenhouse is used to grow plants and is computer controlled. Give two reasons why data from the sensors needs to be converted for use by a computer.
[2]
Answer
Two of:
So that the data from the sensor can be understood by the computer [1]
The output from a sensor is analogue [1]
The input to the computer is digital [1]
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