Appsys ProAudio ADX-32B, Руководство пользователя

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User's Manual
8. DEVICE SYNCHRONIZATION
8.1. General concept
For all signal sources and sinks within a digital audio system, it is required to share a common clock. This
ensures that data processing on all channels and on all devices happens at exactly the same rate. Otherwise, the
individual clocks would drift apart with time, causing the number of samples generated by one device to differ
from the number of samples expected by another – a common symptom for this are to drop-outs, crackles and
dropped samples.
To prevent this, one device (usually the mix console) is the clock master. All other devices operate in slave mode,
following the master's clock signal when generating samples.
Two ways exist to distribute the clock signal from the master to the slaves:
8.2. Synchronization over ADAT
Any ADAT signal can be used for wordclock synchronization as it carries an embedded clock signal. The master
clock device outputs ADAT streams with the master clock timing embedded, and slaves can extract the
embedded wordclock from the stream. Please refer to your equipment's manual how to set the synchronization
to ADAT. If this type of synchronization is used, no additional cabling is required.
Use the "local loop-back” feature to break out additional ADAT signal outputs which can be used as
wordclock source. An example configuration using ADAT sync is shown under
10.1. Digital 24/8
multicore .
8.3. Synchronization over coaxial cable
For larger installations, it is often not convenient to use ADAT for synchronization because of its limitations:
ADAT connections cannot be split easily, and length restrictions may prevent you from reaching all devices. In
such cases, it is better to transmit the wordclock signal over a dedicated, separate connection. For this purpose, a
coaxial cable with BNC plugs is commonly used, combining long reach (>100m) with the possibility to distribute
the signal to several slave devices using “T”-shaped connectors.
The wordclock feature eliminates the need for running an extra coaxial cable beside the Cat5. Refer to
10.2. Digital 48/16 multicore with monitoring and recording splits for an example.
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