As an analog wave enters a digital audio system, the first step is converting the analog waveform into digital information. This process is known as sampling. The waveform can be measured up to 96,000 times a second. Those measurements are then stored in the digital audio system's memory. The quality of the hardware required to make this conversion becomes critical to the sound of digital audio itself.
The number of times per second an analog-to-digital converter samples a waveform is known as sampling frequency. The greater the frequency, the more samples per second are stored of the original waveform. This leads to deeper resolution and higher quality audio. Standard compact discs are sampled at 44.1 kilohertz, or 44,100 times, per second. Many DVDs, gaming systems and HD televisions have sampling frequency rates of 48 kilohertz or 96 kilohertz per second.
Binary, or the digital language used to store these samples, is broken into small chunks of digital information. These "words" provide the digital audio system's memory a road map for storing each of these samples and are composed of a number sequence of 1s and 0s known as bits. The more bits each "word" contains, the more detailed information can be stored for each sample. The number of bits contained in each "word" is known as bit depth. Standard CDs possess 16-bit audio, while DVDs and HD media have 24-bit audio. The higher the bit depth, the more detailed and lush the digital audio will sound.
These samples must be re-arranged in the correct order and sent through a piece of hardware known as a digital-to-analog converter upon playback. Because digital audio is composed of millions of tiny measurements of sound, the converter becomes responsible for smoothing these tiny pieces of information and generating an analog waveform output. This step in the digital audio chain is the most important in determining the quality of a signal.