Model 5601MSC
Model 5601MSC Master SPG/Master Clock System
MASTER CLOCK
Revision 2.2
Page - 91
4.3.2. Configuring the Genlock Capture Range
INPUT
The
Genlock Range
menu item is used to select the type of oscillator to
use when locking to video or 5/10MHz references. See section 2.2.3.
Set this to
Narrow
to use the ovenized oscillator when the frequency
stability of the reference is tightly controlled and within ±0.1 ppm. The
ovenized oscillator provides excellent stability and enables use of the
Slow
lock mode. The
Slow
lock mode allows the 5601MSC to recover smoothly
from a loss of reference or reference shift condition. The Narrow range is
superior to the Wide range in every way except in lock time and lock
range. It is the default setting and does not normally need to be changed.
Select the
Wide
range only when a wide locking range of ±15ppm is
required and when very fast lock times are needed. This may be required
in some post-production facilities where the input reference is changing
occasionally and a fast relock time is desired. Low freerun stability and
slightly higher jitter are the drawbacks of the wide range.
Frequency Ref
Genlock Range
Narrow
Wide
4.3.3. Selecting the Frequency Reference Lock Type
INPUT
The
Lock Type
menu item is used to select how the 5601MSC will relock to
its frequency reference when the reference is lost and then regained, or
experiences a change. See section 2.2.4 for more information.
In
Abrupt
mode, whenever the 5601MSC detects that its internal oscillator is
no longer synchronized to the reference it will make a sudden change to
bring it back into lock. This may cause disturbances to the outputs as the
unit shifts its frequency and phase.
In
Slow
mode, when the 5601MSC detects that its internal oscillator is not
synchronized to the reference it will report
REF JAM NEEDED
on the LCD
display and optionally send an SNMP trap. The unit will then slowly adjust
its internal oscillator to bring it back into lock with the reference. This
gradual correction will not cause any disturbances to the outputs as they re-
phase. This adjustment may take a long time, depending on the size of the
discrepancy between the internal oscillator and reference. If the unit is
required to lock to its reference without delay the user can perform a manual
jam by selecting the
Jam Input
menu item. The
Slow
lock type is only
available if the
Genlock Range
is set to
Narrow
.
Frequency Ref
Lock Type
Slow
Abrupt
If a large shift in the reference occurs while Slow lock mode is enabled, the
outputs of the 5601MSC may be out of phase for a long time while relocking.
The 5601MSC will gradually slew its oscillator to bring it back into phase with
the reference. This slewing action combined with the phase shift may seem to
indicate that the unit is completely unlocked to the reference. This is not a fault
and a manual jam can be performed to force the 5601MSC to lock immediately.