Grass Valley 7600REF User Manual
Page 55
7600 SD/HD/MHD-REF — Instruction Manual
55
Operation
GPS Menu Structure
With the 7600 MHD-REF model, the GPS function will appear on the top
level menu. This opens the menu branch shown in
This menu is detailed below.
•
Status
– see
.
•
PPS Lock
– it the PPS Lock mode is set to On, it only affects the Internal
Free Run mode of genlock. The internal oscillator is then locked to the
GPS reference.
•
Crash Lock
– if the Crash Lock mode is set to On, the output signal is
subject to a single large disturbance followed by a period of approxi-
mately 10 minutes for settling. If the Crash Lock is Off, convergence
may take many hours.
•
ATR
Lock
– ATR (Absolute Time Reference) is covered by SMPTE Pro-
posal 404 and is also known as SMPTE epoch. It defines a starting point
of midnight on January 1st, 1958, at which time all generating equip-
ment is deemed to be phase locked By accurate determination of
current GPS time, any ATR equipment may be locked together again.
ATER also provides a time (and date) source for timecode generated by
the 7600 unit.
If ATR Lock mode is On, the unit will also perform a Crash Lock, inde-
pendently of the Crash Lock mode described above.
•
Site Survey
– a site survey can take up to 2 hours to complete. It may be
initiated at any time, but would normally only be carried out when the
unit is in a fixed installation location with a high quality antenna. Status
of the Site Survey is shown in the Status sub-menu shown in
.
•
Cable Length
– provided compensation for the propagational delay of the
antenna cable.