Model 5601MSC
Model 5601MSC Master SPG/Master Clock System
OPERATION
Revision 2.2
Page - 21
In the event that the frequency reference is lost when locked in Wide mode, the
5601MSC will freerun on its VCXO. Note that this oscillator can freerun at a
frequency outside the Narrow mode lock range which may cause problems for
downstream 5601MSC units. The Wide oscillator is also capable of going
beyond the frequency tolerance specifications stated in ITU-R BT.601 and
SMPTE ST 292-1. Operating outside the range of ±10ppm may cause locking
issues for downstream equipment.
Genlock Range
Oscillator
Lock Range
Time to Lock
Jitter
Free-run Drift
Narrow
OCXO
± 0.1 PPM
>20 seconds
very low
very low
Wide
VCXO
± 15 PPM
<1 second
Low
moderate
Table 2-3: Genlock Range Characteristics
The status of the reference and lock progress can be monitored on the
Lock Status
screen, accessed
by pressing the
STATUS
button and selecting
Lock Status
(see section 4.1.2). The current position
within the tuning range of the selected oscillator is shown as
OCXO center
or
WIDE center
. It is
displayed as a percentage (+100% to –100%) of the total tuning range. This reading gives an idea of
how close to the edges of the tuning range the oscillator is when locked to a reference.
The
Narrow
range OCXO oscillator ages over time and the center frequency may drift. It is important
that despite any drift it retains the ability to lock to a precision frequency source such as GPS or a
rubidium/cesium frequency standard. Such frequency sources are extremely accurate. The oscillator is
guaranteed from the factory to lock to such a reference within ±10% of the center of its tuning range.
The aging of the oscillator is 10% maximum for the first year, and 5% for every year thereafter. This
translates to an expected lifetime of 15 years. If the oscillator locks at over ±90% of its tuning range, a
warning condition will be indicated and the status line will be shown in Red. Keep in mind that the
OCXO center
value is only meaningful when locked to a very accurate frequency reference.
The 5601MSC monitors the condition of both oscillators at all times. If an oscillator problem is detected,
the unit will seamlessly switch to the unused oscillator and report an internal hardware fault. This will
activate the
Hw Fail
message on the front panel and can also send out an SNMP trap. If such a fault
occurs, it is not advisable to power down or attempt to restart the unit. Contact Evertz customer service
for further assistance at +1 905-335-7570 or see
2.2.4. Lock Type Selection
When the
Genlock Range
is set to
Narrow
, the
Lock Type
controls how the 5601MSC will respond
when its oscillator becomes out of sync to the frequency reference. This situation can occur if the
incoming frequency reference changes or is reconnected after a period of absence long enough that
the 5601MSC oscillator has drifted and is no longer synchronized. There are two lock types available:
Slow
and
Abrupt
.
Содержание 5601MSC
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