User Manual

User’s Guide OctaMic XTC © RME
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8.6 Clock Section
Source and frequency of the unit’s clock are configured in Options – Clock. Clock Source offers
several choices for the current clock source: internal clock or external clock (WCK = Word
clock, AES 1 to 4, MADI, ADAT). Sample Rate sets the sample rate for both external and inter-
nal clock.
WCK, AES 1-4, MADI, ADAT (Slave Mode)
Activates the corresponding input as clock reference. In case of a missing or invalid clock
source signal the display of the current sample rate in the lower right corner of the display turns
to red, then the unit changes to its internal clock.
INT (Master Mode)
Activates the internal clock.
With a setting of INT (internal clock) it is mandatory that the clock rate of the sources is
synchronous to the OctaMic XTC. Therefore the external device has to be synchronized to
the OctaMic XTC word clock output or AES/ADAT/MADI output.
The OctaMic XTC thus has to be master, all devices connected to it must be slave. In order to
avoid clicks and drop outs due to faulty or missing synchronicity, a special process called Sync-
Check compares the incoming data and the OctaMic XTC internal clock. The sync state is indi-
cated by a flashing (error) or constantly lit (OK) STATE LED.
A selection of Double and Quad Speed is also possible when using external clock (Slave). If the
OctaMic XTC should operate at 192 kHz, but receives a synchronous word clock of 48 kHz, set
Sample Rate to that value. This way, AD/DA-conversion and digital outputs are configured to
operate in the frequency ranges Single Speed, Double Speed or Quad Speed.
Single Speed
All outputs carry a signal in the range of 32 kHz up to 48 kHz.
DS (Double Speed)
The AES outputs 1-8 carry a signal in the range of 64 kHz up to 96 kHz. ADAT and MADI stay
at no higher than 48 kHz, with the data transmitted in the S/MUX format.
QS (Quad Speed)
The AES outputs 1-8 carry a signal in the range of 176.4 kHz up to 192 kHz. ADAT and MADI
stay at no higher than 48 kHz, with the data transmitted in the S/MUX4 format. Therefore ADAT
is limited to 4 channels (2 per optical output) in this mode.