Nautel NV30LT-N, Руководство по эксплуатации и техническому обслуживанию

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NV30LT-N OPERATIONS & MAINTENANCE MANUAL OPERATING THE TRANSMITTER
PAGE 3.2.128 VERSION 0.1 2015-03-01
Exciter TCXO
The
Exciter TCXO
page (see Figure 3.2.109 ) allows users to calibrate the internal clock to a user
supplied external high precision 10 MHz clock reference (e.g. GPS synchronized 10 MHz clock). Once
this external 10 MHz clock reference is connected, the
10MHz Int-Ext Offset
field will display the
difference between the internal and external frequencies (in ppm). Users can press the
Start
button to
automatically calibrate the internal TCXO to the external reference source; equally, they can manually
enter the measured internal-external offset value into the
TCXO Offset Value
field and press
Apply
.
If no external high precision 10 MHz clock reference is connected, but the actual transmitter carrier
frequency is being measured with a calibrated external frequency counter, operators can manually
offset the internal TCXO by entering the appropriate ppm difference in the
TCXO Offset Value
field.
For example, if the frequency of the transmitter is 1 ppm too high, then a positive 1 ppm should be
entered in the
TCXO Offset Value
field in order to compensate. Similarly, if the transmitter frequency is
too low, enter a negative ppm value. After an adjustment is made, press
Apply
.
To calibrate another exciter, switch to that exciter and repeat the calibration.
Figure 3.2.109: AUI - Exciter TCXO calibration page
NOTE
: You can also adjust the exciter TCXO offset value and run a TCXO calibration from the front
panel UI (see Setting Exciter TCXO Offset, on page 3.2.135 ).