ABSTRACT
Analog audio comprises electrical signals that change over time to represent acoustic
sounds. These voltages can be manipulated in various ways, then converted back to sound
and played through a loudspeaker. Digital audio takes this one step further, using a series
of numbers to represent analog voltages. The process of converting an analog voltage to
equivalent numbers is called digitization, or sampling, and a device that does this is called
an analog to digital converter, or A/D. Once the audio voltages are converted to numbers,
those numbers can be manipulated in many useful ways and stored in computer memory
or on a hard drive. Eventually the numbers must be converted back to a changing analog
voltage in order to hear the audio through a loudspeaker. This job is performed by a digital
to analog converter, or D/A.
