Comparing Analog to Digital
The clock example is a convenient way to understand the differences between analog and digital audio. An analog clock is a continuously flowing representation of the time of day. The hands move smoothly around the clock providing an analogy of the time. A digital clock uses distinct or individual digits to describe the time – it is not smooth flowing, but is characterized by discrete numbers that tell the time.
In audio, an analog signal is a smooth-flowing representation of music or sound. Like a bow on a violin string (an analogy), analog sound is marked by a continuously flowing sound. In digital audio the same bow on a violin string is represented by multiple distinct events, also known as digital samples.
When an audio signal is converted from analog to digital, the smooth-flowing sound of a bow on a violin string is replaced by multiple events or samples.
Each digital sample is a snapshot in time that represents the size and shape of the sound of the violin at that precise moment. A digital signal is a series of multiple snapshots or samples, not a continuous wave. Each sound sample is represented by digits, either zeros or ones. There are so many samples that the human ear perceives the digital sample of the analog wave as a smooth-flowing continuous sound. For example, on a Compact Disc, there are 44,100 digital samples for each second of music stored on the disc.