Nautel XR6, Operation And Maintenance Manual

Page: 43 / 83

XR6/XR3 Operations and Maintenance Manual Operating the transmitter
Page 2-18 Issue 3.1 2013-03-14
30-Day Drift Estimation
1. Set the XR6/XR3’s clock (see “Setting the clock” on page 2-16 ) according to a selected
independent time standard.
2. After 30 days, compare the XR6/XR3’s clock time to the same independent time standard.
Note the time difference.
3. In the
Calibrate Clock
page, adjust the Current RTC Calibration value until the Delta 30-day
Correction time is as close as possible to the difference noted in Step 2 . NOTE: If the XR6/
XR3’s clock gained time on the standard, the Delta 30-day Correction value should be
negative; If the XR6/XR3’s clock lost time on the standard, the Delta 30-day Correction
value should be positive.
4. Press the
Save
button to store the calibration value.
5. Reset the XR6/XR3’s clock according to the time standard.
6. The calibration is complete.
RTC Frequency Measurement
1. Connect a frequency counter, capable of measuring 512 Hz within 0.001 Hz, to a nominal
512 Hz, 5 V CMOS square-wave on TP51 of the control display PWB (A1A1). Note the
measured frequency.
2. In the
Calibrate Clock
page, adjust the Current RTC Calibration value until the Estimated
FT Frequency value is as close as possible to the measured frequency in Step 1 .
3. Press the
Save
button to store the calibration value.
4. Reset the XR6/XR3’s clock (see “Setting the clock” on page 2-16 ) according to a selected
independent time standard.
5. The calibration is complete.