Ross 4500DR-104-07, User Manual, Page: 132 / 161

132 • NTP Option SRG-4500 User Guide (v7.0)
Figure 15.3 NTP Server Time Stratum Determination
Required Time Corrections
From an NTP Server, the SRG-4500 Master Clock can derive UTC and also add the appropriate time offset and
provide corrected local time. Table 15.1 contains a list of the various corrections which need to be made by the
SRG-4500.
Table 15.1 Required Time Corrections
Offset SRG-4500 Update
1 Earth Speed, Drift
in one day
1ms Leap second corrections are made approximately every 18 months
as determined by International Earth Rotation Service (IERS).
2 Local Time User defined The user usually defines the offset from UTC at time of installation
3 Daylight Saving 1 hour Twice per year
Is GPS
locked?
Server
Time
when no
GPS?
Is the
Lock Lost?
YES
NO YES
NO YES
YES
NO
NO
START
YES
Set Stratum to 16 Set Stratum to 16
Set Stratum to 8
Set Stratum to 1
Set Stratum to 2
Set Timer to 0
Serve Time
when no
GPS?
Is the
Lock Lost for
>1hr?
NO