Sampling Frequency
The original AES10-1991 specification allowed 56 channels at sample rates from 32 to 48 kHz with a tolerance ±12.5%, in part 4.1. It leads to a total range of 28 to 54 kHz. This produced a total of 56×32×54 = 96768 kbit/s, leaving 3.232% of the channel for synchronization marks and transmit clock error.
The 2003 revision specifies different relations between sampling frequency and number of channels. The next list is from the part 5.1 of the AES10-2003 specifications:
- 32 kHz to 48 kHz ± 12,5%, 56 channels;
- 32 kHz to 48 kHz nominal, 64 channels;
- 64 kHz to 96 kHz ± 12,5%, 28 channels.
If the data rate is limited to 48 kHz, then 64 channels take 64×32×48 = 98304 kbit/s. Adding the minimum 8×58 kbit/s of framing produces 98688 bit/s, leaving 1.312% free for timing variation or additional channels.
Both versions of the standard accommodate higher sampling frequencies (for example, 96 kHz or 192 kHz) by using two or more channels per audio sample on the link.
Read more about this topic: MADI
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