Clock Section - RME Audio ADI-8 DS User Manual

7. Clock Section

The ADI-8 DS 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 in-
ternal clock (44.1 and 48 kHz, in DS mode 88.2 and 96 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. When PROCESS DS is activated the selected sample rate is doubled.
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 INTERNAL DA.
Please note that the DA 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 DS 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 probably the most outstanding
feature of the ADI-8 DS. 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 DS has to synchronize itself to the
clock from the word clock output or ADAT/TDIF output of the ADI-8 DS.
The ADI-8 DS 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 Sync-
Check compares the synchronicity of the incoming data with the internal clock of the ADI-8 DS.
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 DS © RME