Ensemble Designs 7465 Sync Changeover Switch - Manual (Page 4)

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Page 4
7465 Sync Changeover Switch and 9465 3G Sync Changeover Switch
Module Overview
Fail-Safe Protection Switch
The Avenue 7465 HD/SD Sync Changeover Switch module and Avenue 9465 3G/HD/SD Sync
Changeover Switch module are fail-safe protection switches for monitoring and switching critical
sync reference signals from any of Ensemble Designs’ reference generators or third-party sync pulse
generators. Ensemble Designs’ generators include: Avenue 5400 Dual Sync Generator and Test Signal
Generator, Avenue 7400 HD/SD Test Signal and Sync Pulse Generator, Avenue 7405 HD Test Signal
Generator, and Avenue 9400 3G Test Signal and Sync Pulse Generator.
When a fault is detected in any of the Primary inputs and the Secondary inputs are verified as good,
the protect switch will activate, causing all of the Secondary inputs to be switched simultaneously to
the module’s outputs, ensuring constant, stable references to a facility. Multiple changeover switches
can be ganged together through the control system. Depending on the application, two or more
Avenue 7465 or 9465 modules may be required to handle all signals that need to be protected.
Three Channels
As illustrated in the block diagram on page 6, these modules are divided into three channels, each
with detection circuits which evaluate input source signal types as configured by the user. The signal
type for each channel can be set locally or remotely. These three channels are referred to in the block
diagram as Channels A, B, and C.
For the Avenue 7465, Channel A tests for HD SDI, SD SDI, ASI and SMPTE 310M signals in terms of
presence and locking. For the Avenue 9465, Channel A tests for these same signals plus 3G. Channels
B and C test for AES audio, Composite Video, Bi-Level Sync and Tri-Level Sync in terms of presence, low
level, high level (overload), and error conditions.
The switch control uses the status of the signal condition from each channel’s signal detector to
determine if the switch will throw from Primary to Secondary. A drop in signal amplitude below a
predetermined auto threshold will trigger the switch. All three channels switch together if any one
signal fails a test.
The user may configure which channels contribute to the decision. Each channel can be disabled
(meaning that it is not tested) if desired. Disabled channels will not test the signal but will still pass the
signal to the output. This allows signals that cannot be tested by the Avenue 7465 or Avenue 9465 to
be used if desired.
Auto Mode
When Auto mode is turned on, a fault in any one Primary signal will cause the switch to automatically
throw to the Secondary signal. With Auto mode turned off, a fault in the Primary signal will generate
an alarm but no switching will take place.
Restoring Primary Signals
Following a fault, the Auto Reset parameter governs how the switch behaves when the Primary signals
are restored. With Auto Reset on, the switch will revert back to the restored Primary reference signals
within a time period pre-set by the user. When Auto Reset is off, manual intervention is needed to
throw the switch back to the Primary reference signals.