A digital signal is one that is represented by a sequence of numbers. A digital audio signal consists of a sequence of numbers, each of which represents the level of the original sound source at a particular instant in time.
Digital is contrasted with analog.
Digital is also used as a pejorative term when describing the sound quality of an audio system. It is associated with a somewhat unnatural sound with harshness and noise in the high frequencies.
Digital signals are discrete in time, due to sampling, and in level, due to quantisation. At some stage in the playback of a digital audio signal it must be converted to an analog signal. The accuracy of the resulting analog signal compared to the original analog sound depends on several factors:
- Quality of the original analog to digital conversion. This depends, among other things, on bit depth and sampling frequency.
- Quality of the digital to analog conversion.
- Timing accuracy of the conversions and at all stages of the manipulation and transmission of the digital signal.
©Wayne Butcher