[LAU] Open Sound Interface project beginnings

[Fons Adriaensen]

On Sat, Oct 29, 2011 at 08:58:46AM -0500, Charles Henry wrote:
 
> I have a few questions
> Is digital audio syncronized or packetized?  What's the clock rate?
> What's the data transfer bandwidth? 

There's no single answer to that. ADAT (AFAIK) is synchronised,
but MADI certainly isn't as it can allow variable sample rate.

For MADI the logical bit rate is 100 MHz, or 125 MHz physical
due to 4B5B encoding (which allows recovery of the clock at the
receiver), and this is independent of the actual sample rate.
Any remaining capacity is filled by sync words. This is used
(at 44.1 or 48 kHz) either for 56 channels with 'varispeed'
up to +12.5%, or for 64 channels without the varispeed (the
latter is how I guess it is used in most installations). For
96 kHz the number of available channels is halved. Samples
are 32 bit, with 24 bits used for the actual audio data and
8 for various signalling bits.

> Is there an IC you can use just like adc/dac?

No idea. But the format isn't complicated at all.

Ciao,

-- 
FA