Reference restore – Grass Valley 8900GEN-SM User Manual
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8900GEN-SM — Instruction Manual
Configuring the Genlock Submodule
Reference Restore
When the Primary source has failed and the module has switched to the
Secondary, the following controls allow you to set the module to switch
back to the Primary automatically or manually when it is valid and locked.
You may also set the amount of time before the Primary is restored.
•
Switch to Primary
– set this control to
Manual
if you wish to manually
return to the Primary reference when it becomes valid and locked again
or
Auto
to allow the module to switch back to the Primary reference.
•
Reference Switchback Delay
– when the control above is set for
Auto
, set the
amount of time to allow between switching from the Secondary refer-
ence back to the restored Primary. The switchback time has a minimum
recovery time of 30 seconds to assure that the Primary is locked and
valid before the module switches back to this source.
Primary – Secondary Phase Difference
This graphic shows the total phase difference between the Primary and Sec-
ondary reference signals when they are set to different sources. When the
bar is green and remains in the area before the horizontal indicator, the two
references are in a range where switching between the two will show no
measurable disturbance in the output video (about 72 ns of delay).
When the phase difference is larger than the recommended amount, the bar
will indicate by showing a second red bar. This indicates that the phase dif-
ference is now such that switching between the two references will show a
disturbance in the output video. This can be caused by a loss of one of the
references or a mis-adjustment in the reference output delay of either refer-
ence. The total phase error shown in this graphic represents about 1 uS.
If the red bar appears, check the System Config page for the presence and
lock status of both the Primary and Secondary references. If there is a
timing difference, use the Genlock web page timing controls to bring the
two references into the green bar range. Refer to the
for a detailed description for using this function.