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<font size="-1"><font face="Tahoma"><big>I have a technical question
for Bill Tracey / Phil Harman.<br>
<br>
In my experiments with WinUSB, I have finally been successful in
sending/receiving data to/from the Ozy-Mercury combo.<br>
As a first test, I want to send some PCM data to the DAC of Mercury, to
listen to the output through the speakers.<br>
<br>
And this is where the synchronization question arises.<br>
<br>
I read that the DAC sampling rate is fixed at 48 kHz. Fine. So care
must be exercised to not starve or overflow the DAC.<br>
At first I thought that there was some sort of FIFO, whose filling
status could be queried, allowing the sending program<br>
on the PC to adjust its pace to that of the DAC. But looking at the
docs, I haven't seen any possibilities to do this.<br>
<br>
So the only other possible way is to use the incoming data stream as a
"clock" signal, taking into account that it can<br>
have 48, 96 or 192 kHz as sampling frequency.<br>
<br>
My questions are :<br>
<br>
1) Is that true ? In other words, are the ADC, DAC and FPGA clocks in
the Mercury card all phase locked together ?<br>
<br>
2) If 1) is true, how should I behave when e.g. the input data have a
sampling frequency of 96 kHz ? Should I send<br>
an output frame every two input frames, or should I send the output
frames at the same rates of the input ones,<br>
repeating the data if need be ?<br>
<br>
Thanks<br>
<br>
73 Alberto i2PHD<br>
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