Representing Sound

Sound is an analogue signal — it varies continuously. Computers, however, work with digital (discrete) data. This lesson explains how sound is converted from analogue to digital and the factors that affect the quality and file size of digital audio.

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Analogue vs Digital

• Analogue signals are continuous — they change smoothly over time. Real-world sound waves are analogue.
• Digital signals are discrete — they are made up of distinct, separate values. Computers store data digitally as binary numbers.

To store sound on a computer, the analogue sound wave must be converted into a digital representation through a process called sampling.

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Sampling

Sampling is the process of measuring the amplitude (height) of a sound wave at regular intervals and recording each measurement as a binary value.

The device that converts an analogue sound signal into digital data is called an Analogue-to-Digital Converter (ADC). To play digital sound back through speakers, a Digital-to-Analogue Converter (DAC) is used.

How Sampling Works