Model 5700MSC
Master Clock System
Revision 1.0
Page - 3
With either the
GNSS
Mobile
or
GNSS
Fixed
menu choices, the ovenized oscillator inside the
5700MSC will lock to the 1PPS pulse from the GNSS antenna. This provides a very accurate
frequency reference to the unit. The high precision time and date provided by the GNSS
antenna is used to phase the outputs of the 5700MSC by referencing them to a specific point in
GNSS time. Multiple 5700MSC units locked to GNSS will all have the same phase on their
outputs. This also means the time reference will be forced to GNSS.
•
Ten MHz
– The 5700MSC will look for a 5MHz or 10MHz reference on its reference loop input,
frame reference 1, or frame reference 2. The 5MHz/10MHz reference should come from a
source that has higher stability than the internal oscillator of the 5700MSC such as a Rubidium
or Caesium frequency standard. A 5MHz or 10MHz reference does not provide any phase
information and the phase of the outputs will not be the same between different 5700MSC units.
•
Video
– The 5700MSC will genlock to an analog black burst or HD tri-level reference applied to
its reference loop input, frame reference 1, or frame reference 2. The frequency stability of the
5700MSC will be only as good as that of the reference input. The phase of the outputs will be
aligned to that of the reference input.
•
Internal
– The 5700MSC will free run on its internal high stability ovenized oscillator. Select this
option if no external reference is available to the unit.
•
1588
– The 5700MSC can synchronize with a PTP master to determine a frequency reference.
There are three other menu items that control how the 5700MSC locks to its reference. These are
Genlock Range
,
Genlock Source
, and
Lock type
. Press the
HELP
button for a short description on
what each menu item does.
1.5.
SELECTING AND CONNECTING TIME REFERENCES
Once the desired frequency reference has been selected and the antenna/reference connections have
been made, the time reference should be selected. The time reference is how the 5700MSC obtains
time and date for the system clock. Press the
INPUT
button to access the input menu. Return to the
root level by pressing
ESC
a few times. Select the
Time
menu using the control knob and press
SELECT
. Use the
Reference Src
menu item to choose a time reference for the unit. There are other
menu items that control how the 5700MSC handles the time reference. Press the
HELP
button to
identify the function of each item.
•
GNSS
– When a GPS or GLONASS receiver is connected to the unit, it can obtain continuous
time and date updates from GNSS. If the frequency reference has been set to one of the GNSS
modes, the time reference will also be forced to GNSS. However it is also possible to use a
frequency reference other than GNSS (such as video) and still use GNSS as a very accurate
time reference. See note above regarding GLONASS operation.
•
VITC
– The 5700MSC will look for Vertical Interval Time Code on the selected line of a black
burst signal that is applied to the reference loop input, frame reference 1, or frame reference 2.
It can also decode date information from the user bits in several different formats. In order to
use VITC as a time reference, the frequency reference must first be set to
Video
.
