Studio Technologies 5401A, Руководство пользователя

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Model 5401A User Guide Issue 4, August 2021
Studio Technologies, Inc. Page 17
Model 5401A
DANTE LEADER CLOCK
Failover Clock Source: This is a configurable field
with two choices: Internal and Dante.
This configuration choice selects which timing source
will be used should the Model 5401A’s selected main
clock source become unavailable. Specifically, the
failover source will be used if a valid sync source is
not connected to the sync input. If Internal is selected
then the unit’s crystal oscillator will be utilized as the
Leader clock source should a valid sync input signal
be unavailable. If Dante is selected then the failover
source will be the timing signal derived from the Model
5401A’s Dante interface.
From a performance standpoint it’s preferable to se-
lect Internal. This ensures that the best clock perfor-
mance can be obtained should the failover condition
be active. However, selecting Dante would allow an
interesting, albeit obscure, alerting feature to become
active. In the Dante Controller application, a device
such as the Model 5401A that has been selected as
the Preferred Leader with an external source allowed
will have an error condition occur if the Model 5401A’s
Dante interface doesn’t detect an external reference
being applied. And losing the external reference is
what the Model 5401A’s circuitry will do should failover
be activated and Dante selected as the failover
source. In this way, a Dante network user could be
alerted to a clocking issue should the Model 5401A
lose its sync input source.
However, having an error condition reported in the
Dante Controller application is probably not terribly im-
portant. The Dante SYNC LED, located on the Model
5401A’s front panel, will also offer a clear indication of
a loss of an external sync input signal. This LED will
typically slowly flash green when the Model 5401A is
functioning correctly as the Leader clock for the Dante
network. However, should the unit be configured to
use an external sync input signal and a valid one is not
present, the SYNC LED will flash orange to indicate
this loss of lock and that the failover source is in use.
In addition, the display will provide a text indication
of this condition.
Force Preferred Leader: This is a configurable field
with two choices: Disabled and Enabled.
This function impacts how the Model 5401A will control
a Dante network’s selection of which device is going
to serve as the Leader clock. As the main reason for
the Model 5401A’s existence is to serve as a Leader
clock, in most applications the unit should be serving
in that role. By forcing the Model 5401A to be a Pre-
ferred Leader clock it helps to ensure optimal Dante
network operation. By enabling this configuration, us-
ers of the Dante Controller application will not be able
to accidentally disable the Model 5401A as a Preferred
Leader. One can observe exactly what is meant by
the term Force Preferred Leader by unchecking the
Model 5401A’s Preferred Leader check box in Dante
Controller. After a short interval the box will automati-
cally return to the enabled (checked) state.
How the Model 5401A handles forcing the Dante net-
work to be a Preferred Leader clock and, if applicable,
automatically supporting an external clock input is not
trivial. This ability to control Dante network opera-
tion is part of the unit’s “secret sauce.” If the Model
5401A’s clock source is configured for Dante then
the Model 5401A will force off (uncheck) the Enable
Sync to External selection in Dante Controller. If the
Model 5401A’s main clock source is configured for
Internal or Sync Input then the Model 5401A will force
on (check) the Enable Sync to External configuration
in Dante Controller. This will apply as long as this
specific Model 5401A is acting as Primary Leader,
Leader, or AES67 Leader.
Submit: A Submit button is located below the Force
Preferred Leader field. For any changes made to the
three configurable fields on the Main menu webpage
to be saved and acted upon the Submit button must
be pressed.
Current Clock Source:
This is a display-only field
with choices of Internal, Internal (Failover Active),
Sync Input, Dante, and Dante (Failover Active).
The text Failover Active will display in red as a warn-
ing of an abnormal condition that warrants interven-
tion. The current clock source field can also display
--- which indicates a major hardware error and would
warrant contacting the factory.
When Internal is displayed it indicates that the Model
5401A’s internal temperature-stabilized oscillator is
being used as its timing reference. When Internal
(Failover Active) is displayed an abnormal condition
is occurring. In this case, the Model 5401A has been
configured to use an external sync signal as the main
clock source but a valid one is not available; it is