Sonifex AVN-GMC, Руководство пользователя

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3 Grand Master Clocks, AVN, Ravenna & AES67
3. Grandmaster Clocks, AVN,
RAVENNA & AES67
Sonifex joined the Ravenna group in 2012 and the AVN product range is the
result of our R&D in the area of audio over IP. If a Sonifex product starts
with the letters ‘AVN’, then it’s part of the family of products which can
send audio to each other over an IP network (AoIP).
RAVENNA (of which AES67 is a subset) allows for the distribution of audio
across a network. For this to be possible, each of the nodes needs to be
time synchronised with one another. Ravenna uses PTP (Precision Time
Protocol, as defined by IEEE1588-2008v2) time stamping to achieve this,
which both distributes the network time and also works out the latency
involved in the delivery and adjusts the time at each node accordingly. Unit
configuration is achieved easily either with the front panel controls or the
webserver, including the setup of the PTP profile. A Grandmaster Clock
(GMC) is a source of all the networks’ time and should be synchronised to
GPS.
AVN and other manufacturers RAVENNA products will use the time
distributed by the AVN-GMC to create internal audio clocks that are all
highly synchronous to one another, so that audio derived from one unit will
playout at precisely the same rate when sent to another.
AES67 is a standard released by the Audio Engineering Society to enable
interoperability of Audio over IP devices from different manufacturers and
there is a specific subset of RAVENNA that will implement the methods and
protocols as required.