Clock Section - RME Audio ADI-8 PRO User Manual

7. Clock Section

The ADI-8 PRO provides an outstanding clock section with professional features you won't
find anywhere else. The unique Intelligent Clock Control (ICC) enables a flexible operation with
internal clock (44.1 and 48 kHz), external word clock or the digital input signals. These options
are easy to understand and easy to use thanks to a clear display of the corresponding lock and
sync state.
A/D
The clock source of the AD-converter can be Internal (quartz crystal), External (BNC word
clock) and Input (the digital input signal TDIF or ADAT). Internal 44.1 kHz or 48 kHz sample
rate is available.
D/A
The same options are available for the DA-converter.
The key DIGITAL INPUT determines the digital input being used and the clock source in case
INPUT was activated before.
As not all combinations of clock settings make sense some of them are blocked. The limita-
tions mainly affect TDIF operation and the setting Clock D/A INTERNAL.
Please note that the D/A key has priority. In case an allowed combination can't be set simply
press the D/A key, set A/D as desired, and set D/A back to its last state.
The Lock state of the ADI-8 PRO is indicated by a blinking (error) or constantly lit (Ok)
EXT. or INPUT LED in the Clock section.
Clock Mode D/A Internal
Clocking the DA-converter from the internal quartz crystal is propably the most outstanding
feature of the ADI-8 PRO. This technique provides simply the best sound quality, as the
internal clock has very low jitter, so that the DA-converters can achieve the highest signal to
noise ratio and lowest distortion.
The setting Clock D/A INTERNAL requires a synchronous operation of all devices. To guar-
antee this the external device connected to the ADI-8 PRO has to synchronize itself to
the clock from the word clock out or ADAT/TDIF out of the ADI-8 PRO.
The ADI-8 PRO has to be master, all attached devices slave. To prevent a not better but
worse sound quality caused by imperfect or even no synchronisation a special method called
SyncCheck compares the synchronicity of the incoming data with the internal clock of the
ADI-8 PRO. The actual state is indicated by a blinking (error) or constantly lit (Ok) ADAT
or TDIF LED in the DIGITAL INPUT section.
In clock mode D/A INTERNAL the clock choices EXTERNAL and INPUT of the AD-section do
not make sense, as the clock at the digital output has to be synchronous to the internal clock.
Therefore A/D INTERNAL is automatically activated and cannot be changed.
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User's Guide ADI-8 PRO © RME