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8. Clock Section
The ADI-2's unique clock section layout makes it easy to use, easy to understand and easy to
read. Additionally RME's Intelligent Clock Control (ICC) enables a flexible operation of the AD-
and DA-converter with internal clock or the digital input signals. A clear display of the lock and
sync state further improves the clock section's usability.
The chosen clock state is valid for both AD- and DA-conversion simultaneously.
The key INPUT determines both the digital input being used for the DA-converter (coaxial or
optical), and the external clock source in case CLOCK - INPUT has been selected. The lock
state of the ADI-2 is indicated by a blinking (error) or constantly lit (Ok) input LED (COAX,
OPT).
In master mode (internal clock) a missing digital input signal causes the INPUT LED of the
chosen input to flash. When using the ADI-2 as AD-converter only, the flashing LED becomes a
normal state. In case an input signal is present but not in synchonisity to the internal clock, the
CLOCK LED will flash.
Using external clock, the ADI-2 shows the range of the input signal's sample rate via the
CLOCK LEDs. An external signal in Double or Quad Speed will cause the DS or QS LED to
light up.
Key CLOCK
This key sets the sample rate of the ADI-2. The unit will then be in
clock mode master. However, with INPUT selected, the sample
rate of the present digital input signal will be used as clock refer-
ence, the device then turns into clock mode slave.
Each push on the key CLOCK raises the sample frequency. When
reaching the setting INPUT, the DS LED lights up. The chosen
frequency is now multiplied with a factor of 2. When reaching
INPUT again, the QS LED lights up. The chosen frequency is now
multiplied with a factor of 4. When reaching INPUT once again, the
sample rate is back to 32 kHz and the scheme starts from the be-
ginning. The flow diagram to the right shows all available sample
rates.
Clock mode D/A Internal
Clocking the DA-converter from the internal clock requires a synchronous operation of the at-
tached device. To guarantee this the external device connected to the ADI-2 has to synchro-
nize itself to the clock from SPDIF, AES or ADAT output of the ADI-2.
The ADI-2 has to be master, all attached devices slave. To prevent clicks caused by imperfect
or even no synchronisation, a special method called SyncCheck compares the synchronisity of
the incoming data with the internal clock of the ADI-2. The actual state is indicated by a blink-
ing (error) or constantly lit (Ok) CLOCK LED.
Only one device can be master in a digital system! When the ADI-2 operates with internal
clock, all other devices have to be Slave.
User's Guide ADI-2 © RME
11
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