NTS 01 Rev 1 – User Manual March 2006
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Page 16 of 31
Tekron International Ltd
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Antenna Cable Delay Compensation
Measured in nanoseconds. All antenna systems introduce delay due to the characteristics of the
antenna cable. NTS01 compensates for this delay to optimise the precision of the output signals.
The standard 30m cable supplied with NTS01 introduces 120nS of delay, so for this cable, the
Antenna cable delay is set as “120”. In most practical situations, external factors such as
network topology will have much greater effect on the precision of overall system
synchronisation, so that precise setting of this parameter becomes irrelevant. When the NTS01 is
operating in Slave mode (synched to incoming IRIG-B on P4), this parameter has no meaning,
and is shown greyed out.
Mask Angle
T
he elevation above the horizon below which specific satellite signals will not be used in time
and position calculations. Factory default value is 5 degrees. Range: 0-90.degrees.
Where the antenna view of the sky is severely restricted, in rare circumstances, altering this
value may give some fine improvement in stability of the time signal. Increasing the angle
reduces the likelihood of errors being introduced by multi-path signals from low elevation
satellites (typically caused by reflections off land-based obstacles), but narrows the overall field
of view. When the NTS01 is operating in Slave mode (synched to incoming IRIG-B on P4), this
parameter has no meaning, and is shown greyed out.
Test Mode
Test Mode forces NTS01 to provide all outputs as if it is in sync at all times, even if there is no
antenna attached, or no sync source on P4. The sync relay will be on at all times, regardless of
the true sync state. During test mode the NTS01 display will flash a warning.
This mode should NOT be used during normal operation.
Suppress Out of Sync Indications
A similar mode to “Test” mode, but if this option is selected, the Sync Relay will still indicate
the true sync state of the NTS01 unit. All other outputs will operate as if the unit is synchronised
at all times.
Suppress Outputs When Out of Sync
The Network Time Server Ports (NTS) and the code output on P5 are normally active at all
times, even when the NTS01 unit is not synchronised. Selecting this option will cause all of the
outputs to be suppressed. NTP clients polling the Time Servers will still receive responses, but
the responses will contains null time stamps, and the “sync” status flag in the responses will not
be asserted.
Sync to IRIG-B Input
If an IRIG-B signal (with IEEE1344 extensions active) is input on P4, (RS422 signalling
protocol required!) then the NTS01 will synchronise to it if this option is selected. The usual
source of such a signal would be from the P5 output of another NTS01 unit.
