Electronics project notes/Audio notes - Digital sound communication

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This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)


Typically external

S/PDIF

See also:

AES3

ADAT

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

ADAT has referred to two distinct things

Historically (and now rarely) to the Alesis Digital Audio Tape, a way of storing eight tracks digitally onto Super VHS


And much more typically to the ADAT Optical Interface, more commonly known as ADAT Lightpipe or often just ADAT, also from Alesis.

It looks the same as TOSLINK / S/PDIF, but speaks a different protocol, and somewhat faster.


It carries only 24 bit audio channels (though some devices will effectively work on the higest 16 for practical reasons).


Its speed lets it carry up to eight at 48kHz.

Or, with the common S/MUX extension, up to four at 96kHz, or two at 192kHz


See also:

Typically internal

I2S

(Note there is no relation to I2C)

I2S (sometmimes IIS), Inter-IC Sound is meant to standardize PCM data between closeby chips.

As I2S doesn't spec a plug, or how to deal with longer cables (impedance and such), it is typically only used between components within a device.


Technically:

  • lines are: bit clock, left-right clock, data, ground
Separating clock and data means somewhat lower jitter (and indirectly latency) than buses that don't.
in applications often a little more[1]
~2.4V threshold so can be used in 3.3V devices
  • PCM data
16, 24, or 32-bit
mono or stereo
8kHz to 192kHz (verify)


https://en.wikipedia.org/wiki/I²S

On DACs