Editing Direct Stream Digital (section)

{{Short description|System for digitally encoding audio signals}}
{{Use mdy dates|date=January 2016}}
{{Essay-like|date=March 2014}}

{{Infobox storage medium
| name = Direct Stream Digital
| logo = [[File:DSDlogo.svg|class=skin-invert|140px|DSD logo]]
| image =
| caption =
| type = {{unbulleted list|Audio recording process|Disc format}}
| encoding = Digital
| capacity =
| read = DSD
| write = [[Super Audio CD]]
| standard = ISO/IEC 14496-3
| use = Audio recording
| extended from = 
| extended to = present
| released = 1999
}}

'''Direct Stream Digital''' ('''DSD''') is a [[trademark]] used by [[Sony]] and [[Philips]] for their system for digitally encoding audio signals for the [[Super Audio CD]] (SACD).

DSD uses [[delta-sigma modulation]], a form of [[pulse-density modulation]] encoding, a technique to represent audio signals in digital format, a sequence of [[Audio bit depth|single-bit]] values at a [[sampling rate]] of 2.8224&nbsp;[[megahertz|MHz]]. This is 64 times the [[CD audio]] sampling rate of [[44.1&nbsp;kHz]], but with 1-bit samples instead of 16-bit samples. [[Noise shaping]] of the 64-times [[oversampling|oversampled]] signal provides low [[Quantization (signal processing)|quantization]] noise and low [[distortion]] in the audible bandwidth necessary for [[high resolution audio]].

DSD is simply a format for storing a [[Delta-sigma modulation|delta-sigma]] signal without applying a [[decimation (signal processing)|decimation]] process that converts the signal to a [[Pulse-code modulation|PCM]] signal.