Digital Audio is a sound wave which has been converted into a series of numbers. The device which does this job is called a D/A A/D converter. (Digital to Analog Analog to Digital) The number of A/D, D/A converters available increases the capability of the Digital Audio Device. It also greatly increases the price of that device.
The numbers represent that sound wave at a given moment in time. The sound is in fact “sampled.” Since sound changes over time, a great number of Digital samples are required to represent the sound.
The more times the sound is “sampled” in a period of time the
more accurate the digital conversion. This is called the “sample
rate.” The “sample
rate” for CD quality sound is 44,100.
This means that the sound wave is divided into 44,100 samples for each second of the sound. Those samples are stored and put back together to recreate the sound file.
The “bit rate” of a sample represents the number of bits of information which each digit represents. In an “8 bit” sample each number represents 8 bits of information, while a “16 bit” sample represents 16 bits of information. The “resolution” or accuracy of a “16 bit” sample will be twice that of an “8 bit sample.
Three factors then affect the sound quality and accuracy of Digital Audio. They also affect the amount of memory required to store and reproduce that audio. These factors are:
Digital Exercise #1