深白色 (Arys Chien) 寫:
RME 的 clock 是很穩，只是切換的時候偶爾會怪怪的，切不過去。尤其是跟 single/double rate 有關的時候。
Most people think that
""a digital audio recorder would know the sampling rate of an incoming signal, either by reading a hidden flag in the data stream or by measuring the time between samples....."" And you'd be right most of the time....
but not always.
Although there is a flag indicating a digital audio stream's sampling rate...but the information it conveys is limited....
The S/PDIF format (IEC958) mandates a subcode flag identifying the current sampling rate as
either 32-, 44.1-, or 48 kHz. What happens when a S/PDIF device outputs an 88.2- or 96 kHz audio stream? One of the three sampling-rate flags
must still be indicated, even if it is wrong.....
In the AES/EBU format.. things are a little better..
It has a fourth subcode flag called
“sampling rate not indicated.” ......That should be used when the actual sampling rate is not 32-, 44.1-, or 48 kHz......An additional set of subcode bits in the AES3 spec can properly flag other sampling rates, but it's not clear how many manufacturers use this potentially more useful but optional flag....
therefore..unless RME and Blue have the same agreement on reckon the Flag header stands for "DS"mode...
There is no resaon either "Master" or "Slave" unit would change sampling status automaticly......
my 2 cents..
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