Network Technologies DVB-ASI to IP - Manual (Page 59)

ASI-IP-GTW User's Manual
Page 59
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1PPS. 50 ohm TTL input for a 1 pulse-per-second signal.
For physical parameters of the 1PPS port, see appendix B.
4.1.3 Operating the 1PPS/10MHz interface module
A new top-level tab named “GPS” appears in the user interface of the
ASI-IP-GTW units with the interface mounted. The control part of this
tab only consists of a ComboBox where the lock mode is selected.
Figure 31 shows the layout of the page.
Figure 31. GPS tab
The control parameter simply consists of a combobox:
27MHz lock mode: Select the lock mode for the internal 27MHz. Set
this parameter to “Disabled” if you don’t want to use the GPS board.
Set to “Lock to external 1PPS” or “Lock to external 10MHz” if you want
to lock the system clock to the reference signal.
The status parameters show the current state of the lock mechanism.
The parameters are as follows:
Regulator state: Shows “Idle”, “Waiting” or “Fine tune” dependent on
the selected mode. In the “Waiting” state, the ASI-IP-GTW waits for a
valid input signal to lock to. After some seconds with valid input signal,
the regulator enters the “Fine tune” state which indicates that the
system clock is locked OK. The “Idle” state indicates that the regulator
is disabled.
Current phase offset: This is an integer number that gives an
indication of the current phase offset between the internal and external
clock sources. It’s absolute value should be below 100 in the stable
phase.