Nautel NX25, Operation And Maintenance Manual

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NX300 Operations and Maintenance Manual Operating the transmitter
Issue 3.0 2012-11-01 Page 2-93
Exciter Clock Calibration
The
Exciter Clock Calibration
page (see Figure 2.69 ) allows you to calibrate the internal clock
reference to an external 10 MHz clock by pressing the
Calibrate
button. Both exciters are calibrated
at the same time. Note: typically, a value change is not required.
The exciter clock may also be synchronized to a reference source, either an external 10 MHz
reference connected to A11A1J8 or a Nautel optional GPS sync PWB. The frequency and phase
option is applicable for combined systems only. The exciter reference will lock to the external source
frequency within 10 mHz (0.01 Hz) using the 10 MHz sync input, to within 2 mHz (0.002 Hz) using
the GPS sync card without an antenna, and to within the the quality of the GPS system when using
the GPS sync card with an antenna.
Figure 2.69: System Settings - Exciter Clock Calibration
Procedure to calibrate the exciter clock:
1. Select the
Exciter Clock Calibration
option from the left side of the
System Settings
page to open a related window on the right side of the page.
2. Connect an external 10 MHz source to A11A1J8, verify a value near 10 MHz displays in
both
External Clock Frequency
fields, and press
Calibrate.
Procedure to synchronize the exciter clock:
1. Select the
Exciter Clock Calibration
option from the left side of the
System Settings
page to open a related window on the right side of the page.
2. Connect a source (10 MHz input or GPS sync).
Enable/Disable Frequency
If Disabled (default), no other
settings are required.
If Frequency, select Sync Source
(10MHz Sync Input or GPS Sync
Card). Selecting GPS Sync Card
also displays the Antenna Present
drop-down field (select Yes or No)
If Frequency and Phase (combined
systems only), enter Phase Offset.