Table of Contents
Advertisement
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 cho-
sen 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 synchronicity 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 SPDIF or
AES signal in Double or Quad Speed will cause the DS or QS
LED to light up. With ADAT the input sample rate is always
Single Speed. The real sample rate (Double or Quad Speed)
therefore has to be set up manually by the user (push the
CLOCK button so that either DS or QS light up).
Button CLOCK
This button 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 reference, the device then turns into clock mode slave.
Each push on the button CLOCK raises the sample frequency.
When reaching the setting 48 kHz the DS LED lights up. The
chosen frequency is now multiplied with a factor of 2. When
reaching 48 kHz (now 96 kHz) again, the QS LED lights up. The
chosen frequency is now multiplied with a factor of 4. When
reaching 48 kHz (now 192 kHz) again, the INPUT LED lights up,
then INPUT DS, then INPUT QS. Next the sample rate is back to
32 kHz and the scheme starts from the beginning. In case of
SPDIF the incoming signal defines the status DS and QS. A
manual selection is only necessary with ADAT.
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 synchronize
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 synchronicity of
the incoming data with the internal clock of the ADI-2. The actual state is indicated by a blinking
(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
Advertisement
Table of Contents
