IEC +AMD+AMD CSV Standard | Digital audio interface – Part 3: Consumer applications. IEC (formerly IEC ) is the International Electrotechnical Commission’s standard on digital audio interfaces. It consists of several parts: IEC General; IEC Software Information Delivery Mode; IEC Consumer. IEC Digital audio interface – Part 3: Consumer applications.
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An AES3 signal can carry two channels of PCM audio over several transmission media including balanced linesunbalanced linesand optical fiber. The standard was first published in and was revised in and The development of standards for digital audio interconnect for both professional and domestic audio equipment, began in the late s  in a joint effort between the Audio Engineering Society and the European Broadcasting Union, and culminated in the publishing of AES3 in Variants using different physical connections are specified in IEC These are essentially consumer versions of AES3 for use within the domestic high fidelity environment using connectors more commonly found in the consumer market.
Of the physical interconnection types defined by IECthree are in common use. Type I connections use balanced3-conductor, ohm twisted pair cabling with XLR connectors.
Type I connections are most often used in professional installations and 6058-3 considered the AES3 standard connector. The hardware interface is usually implemented using RS line drivers and receivers.
This uses the same cabling, patching jec infrastructure as analogue or digital video, and is thus common in the broadcast industry. For information on the synchronization of digital audio structures, see the AES11 standard.
No attempt was made to use a carrier able to support both rates; instead, AES3 allows the data to be run at any rate, and encoding the clock and the data together using biphase mark code BMC. Each audio sample of up to 24 bits is combined with four flag bits and a synchronisation preamble which is four time slots long to make a subframe of 32 time slots. Two subframes A and B, normally used for left and right audio channels make a frame.
Frames contain 64 time slots and are produced once per sample time. This determines the clock rate. At the highest level, each consecutive frames are grouped into an audio block. While samples repeat each frame time, metadata is only transmitted once per audio block.
This is a specially coded preamble that identify the subframe and its position within the audio block. The 8-bit preambles are transmitted in time allocated to the first four time slots of each subframe time slots 0 to 3.
Any of the three marks the beginning of a subframe.
X or Z marks the beginning of a frame, and 609958-3 marks the beginning of an audio block. As stated before there is one channel status bit in each subframe, making one bit word for each channel in each block.
In the case of AES3, the standard describes in detail how the bits have to be used.
IEC – Estonian Centre for Standardisation
Here is a summary of the channel status word: It can be used for synchronization and for logging and identifying audio content. According to John Ratcliff’s Timecode: A user’s guideit is embedded as a bit binary word in bytes 18 to 21 of the channel status data. From Wikipedia, the free encyclopedia. Archived from the original on Bytes 18 to 21, Bits 0 to 7: Time of day sample address code. LSBs are transmitted first. Default value shall be logic “0”. This is the time-of-day laid down during the source encoding of the signal and shall remain unchanged during subsequent operations.
A value of all zeros for the binary sample address code shall, for the purposes of transcoding to real time, or to time codes in particular, be taken as midnight i. Transcoding of the binary number to any conventional time code requires accurate sampling frequency information to provide the sample accurate time.
A low-quality auxiliary channel used as specified in the channel status word, notably for producer talkback or recording studio -to-studio communication.
One sample stored with most significant bit MSB last. If the auxiliary sample is used, bits 660958-3 are not included. Data with smaller sample bit depths always have MSB at bit 27 and are zero-extended towards the least significant bit LSB. During the presence of defective samples, the receiving equipment may be instructed to mute its output.
IS/IEC 60958-3: Digital audio interface, Part 3: Consumer applications
It is used by most CD players to indicate that concealment rather than error correction is taking place. Forms a serial data stream for each channel with 1 bit per framewith a format specified in the channel status word.
Bits from each frame of an audio block are collated giving a bit channel status word.
Even parity bit for detection of errors in data transmission.