Manual

Model 5401A User Guide Issue 2, July 2021
Studio Technologies, Inc. Page 17
are critical to the Model 5401A’s support
of related Dante devices. When Internal is
selected the Model 5401A’s temperature-sta-
bilized, high-performance crystal oscillator
is utilized. This will provide excellent timing
accuracy and consistent long-term perfor-
mance. This source is far superior to that
provided by other standard Dante devices.
This is the correct choice if a high-quality
reference signal is not going to be connected
to the sync input.
When Sync Input is selected the Model
5401A’s sync input function will be utilized.
Using a BNC jack, located on the Model
5401A’s back panel, an external source of
word clock, video reference, or 10 MHz sine
wave can be connected. Circuitry within the
Model 5401A will “lock” (synchronize) the
internal timing signals to the externally pro-
vided reference signal.
Selecting Dante will instruct the Model
5401A to use the clock signal provided by
its Dante interface circuitry as its reference
timing source. The Dante interface circuitry
will either use its internal crystal oscillator or
synchronize to another Dante device on the
associated network. The actual clock source
used by the Model 5401A’s Dante interface
will depend on a setting in the Dante Con-
troller application.
The Model 5401A includes the choice of
Dante as the main clock source only for trou-
ble-shooting or other factory-directed activi-
ties. It’s not expected that this selection will
ever be used during normal Model 5401A
operation. By selecting Dante the excellent
timing performance that can be provided by
the sync input or the internal oscillator would
not be utilized.
Failover Clock Source: This is a configu-
rable field with two choices: Internal and
Dante.
This configuration choice selects which tim-
ing source will be used should the Model
5401A’s selected main clock source be
-
come 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 unavail-
able. 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 prefer
-
able to select Internal. This ensures that the
best clock performance 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 ap-
plication, 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 los-
ing 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 prob-
ably not terribly important. 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.