AES3

AES3 (also known as AES / EBU ) is a standard for transmitting digital audio signals between audio devices. Developed by the Sound Engineering Society (AES) and the European Broadcasting Union (EBU) and first published in 1985 , later revised in 1992 , 2003 and 2009 . ^[1] Some difference in physical connectors is also determined by part of the whole group of standards. A sister system, S / PDIF , is designed as a consumer version of AES / EBU, using a type of connector that is more common in a consumer environment.

Content

Standards

The interface for serial digital transmission of two channels of digital audio data with periodic sampling and linear representation has been standardized in several organizations:

in AES as the standard AES3 ^[1] , the latest edition of 2009, as revised in 2014,
in EBU, as Tech.3250-E standard ^[2] , last publication of 2004,
in IEC , as IEC 60958-4 ^[3] , 2008 standard,
in ITU-R , as recommendation BS.647-3 ^[4] , published in 2011.

Hardware Implementation

AES3 standard complies with the international standard IEC 60958. Three types of physical connection are used, described by IEC 60958:

IEC 60958 type I balanced - three-wire, 110-ohm two-wire cable with XLR connector , used in professional equipment (AES3 standard).
IEC 60958 Type II Unbalanced - A two-wire, 75-ohm coaxial cable with RCA connectors, used in consumer audio equipment.
IEC 60958 type III optical - fiber optic , plastic is used, but sometimes glass, with F05 connectors, is also used in consumer sound equipment.

The AES-3id standard describes the modification of AES3 transmission with a 75-ohm coaxial cable with BNC connectors. Recently, this type of physical connection is used in professional equipment. The same type of cables, commutations and connectors is used as for the transmission of analog or digital video, mainly in the broadcast industry.

F05 - a connector for plastic fiber , better known under the brand name of Toshiba TOSLINK . Prior to IEC 60958 Type II specification was the S / PDIF interface. It is worth noting that the AES / EBU and S / PDIF standards have different electrical levels.

D-25 - 25-pin D-sub type connector, described by AES59-2012 standard for balanced connection of up to 8 analog or digital lines. In accordance with the standard, one D-25 connector can be used for either eight analog inputs (outputs) or eight digital inputs (outputs), but cannot be used for mixed signals - analog and digital, or for mixed analog inputs and outputs . ^[five]

Protocol

AES / EBU was originally developed to support PCM- encoded audio data in two formats - DAT and CD , with sampling rates of 48 kHz and 44.1 kHz, respectively. The AES / EBU standard allows you to transfer data at any sampling rate and restore the clock frequency by decoding the data using a unit code with double phase change ( Biphase mark code , BMC).

The main differences between AES3 and SPDIF ^[6]
	AES3	AES3	AES3id	SPDIF
Resistance	110 ohm	110 ohm	75 ohm	75 ohm
Connection	Symmetrical	Symmetrical	Asymmetrical	Asymmetrical
Used cable	Shielded pair	Category 5 cable	Coaxial cable	Coaxial or optical cable.
Connectors	XLR or D-25	Rj-45	Bnc	RCA or TOSLINK
Signal strength	2 - 7 V	2 - 7 V	1 V	0.5 V
Modulation	double phase change unit code
Subcode Information	ASCII ID text	ASCII ID text	ASCII ID text	SCMS Copy Protection Information
Maximum distance	100 m	400 m	1000 m	10 m
Maximum Resolution	24 bits	24 bits	24 bits	20 bits (optional 24 bits)

Links

European Broadcasting Union, Specification of the Digital Audio Interface (The AES / EBU interface) Tech 3250-E third edition (2004)
Watkinson, John. The Art of Digital Audio Third Edition. - Focal Press, 2001 .-- ISBN 0240515870 .
Watkinson, John (August 1989). " The AES / EBU Digital Audio Interface ". UK Conference: AES / EBU Interface . EBU-02.
Emmett, John Engineering Guidelines: The EBU / AES Digital Audio Interface (Neopr.) (PDF). European Broadcasting Union . Archived on March 28, 2012.
AES-2id-2006: AES information document for digital audio engineering - Guidelines for the use of the AES3 interface. (Downloaded from the AES standards web site; see external links)
Mark Yonge AES3 Channel Status Revisited (unopened) // Line Up. - No. 101 . - S. 20-22 . (inaccessible link)
Bernd Noack. AES3 / AES-EBU channel status byte settings (unspecified) . Archived on March 28, 2012.

Notes

↑ ¹ ² AES3-2009; new multi-part revision published (unopened) . AES (2010). Date of treatment April 23, 2015.
↑ Specification of the digital audio interface (The AES / EBU interface) (unspecified) . European Broadcasting Union . Date of treatment April 23, 2015.
↑ Digital audio interface - Part 4: Professional applications (unspecified) . IEC (2008). Date of treatment April 23, 2015.
↑ Digital sound interface for broadcasting studios (unspecified) . ITU (2011). Date of treatment April 23, 2015.
↑ AES Standardizes Application of 25-Way D-Type Connectors (unopened) (link not available) . TV Technology (2013). Date of treatment April 23, 2015. Archived December 8, 2015.
↑ RaneNote INTERFACING AES3 & S / PDIF (unopened) (PDF). Rane Corp. (2010). Date of treatment April 23, 2015.

[AES3-1] ¹ ² AES3-2009; new multi-part revision published (unopened) . AES (2010). Date of treatment April 23, 2015.

[2] Specification of the digital audio interface (The AES / EBU interface) (unspecified) . European Broadcasting Union . Date of treatment April 23, 2015.

[3] Digital audio interface - Part 4: Professional applications (unspecified) . IEC (2008). Date of treatment April 23, 2015.

[4] Digital sound interface for broadcasting studios (unspecified) . ITU (2011). Date of treatment April 23, 2015.

[5] AES Standardizes Application of 25-Way D-Type Connectors (unopened) (link not available) . TV Technology (2013). Date of treatment April 23, 2015. Archived December 8, 2015.

[6] RaneNote INTERFACING AES3 & S / PDIF (unopened) (PDF). Rane Corp. (2010). Date of treatment April 23, 2015.