Calibrate The Master Time Base - Ramsey Electronics COM3010 User Manual

GENERATE
Modulation

5.20 Calibrate the Master Time Base

The COM3010's Master Time Base is a voltage controlled TCXO with an accuracy of better
than ± 0.1ppm over a given time and temperature. The time base is easily adjusted to any
calibrated standard or reference available.
Any frequency within the receiver's range can be used for calibration, however, it is
recommended that the highest frequency possible is used for best accuracy. A generator
locked to a 10MHz standard or a harmonic of the 10MHz standard makes an ideal reference
for calibration. If a generator is available use the highest frequency possible up to 1GHz. In
the example below we will use 955 MHz from a signal generator locked to a standard.
The layout of the Frequency Calibration Menu is as follows:
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On the GENERATE screen:
The Cal: Field displays the DAC (digital to analog converter) value. This value can be any digit
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from 0 to 4095.
The FR Field displays the Receiver Frequency. It should be set to the user's reference
frequency. The default frequency is 999.15MHz. This is the frequency that is used at the
factory to calibrate the unit during final testing.
The IF.1 Field is the frequency counted by the IF counter.
The [Auto Cal] field selects the automatic calibration feature.
On the RECEIVE screen:
[Abort] allows the user to exit the Frequency Calibration Menu without making any changes to
the COM3010's calibration.
[Exit&Save] allows the user to Exit the Frequency Calibration Menu and save all changes made
to the COM3010's calibration.
The ppm Meter displays the difference in parts per million between the Receive Frequency
Setting and the actual received signal counted by the IF counter.
The RSSI Meter provides an indication of receive signal strength.
USER CALIBRATIONS
TX Level RECEIVE
Seq/Reg Counter
73
Level Meters
Freq Meters