Grass Valley 8985FS v.1.2.0 - Manual (Page 42)

42 8985FSP/FS/PRC — Instruction Manual
Configuration
for outputting a Ref 2 frame bus), or Input , the reference is taken from the
input video. The signal and genlock status of each reference source will be
reported in the Status and Genlock columns.
When a Secondary reference source is selected that is different than the Pri-
mary, the module can be configured to switch automatically to the Sec-
ondary selected if the Primary is lost or becomes unlocked or invalid. If you
do not want this action of switching to a secondary, set the Primary and Sec-
ondary sources to the same source or set the Switch to Primary control
below to
Manual .
Refer to 8000GEN-SM Reference Timing on page 23 for an overview of using
the 8900GEN-SM submodule for reference timing. Also refer to the
8900GEN-SM Installation Manual available online for complete details for
using this submodule for timing applications.
Reference Restore
If the Primary source has failed and a Secondary source is selected and
valid, the following controls allow you to set the module to switch back to
the Primary automatically or manually and determine 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 or 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 is provided to show the total phase difference between the
Primary and Secondary reference signals. 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 distur-
bance in the output video (approximately 72 nS).
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 approximately
1 uS.