ITCR Base Radio User's Guide
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10
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9/8/2011
7.
Set the VSA to the center frequency of the channel and set it to demodulate the
16 ksym/second π/4-DQPSK emission and measure the error frequency which is
referenced to the VSA center frequency.
To adjust the master crystal reference oscillator parameters:
1.
First, check the factory default setting for the crystal reference parameter by
typing
i.
cal
2.
Note the value for “xo” in the cal factors table that is displayed.
3.
At the XtermW command line, type:
i.
cal,set,xo,xx
ii.
where xx is some value close to the original factory set value.
4.
Use trial and error to determine the set point for the xo value to achieve the
desired carrier frequency accuracy.
To reset the XO tuning parameter to the factory setting:
Power cycle the radio.
4.4
Measure and Adjust Output Power
Caution: Avoid unnecessary adjustments.
Exercise caution when setting I
and Q gain values as damage to the radio can occur if gains are set too
high.
Base radios are rated for 75W PEP. To achieve this power radios are pre-calibrated
at the factory. If additional tuning is required, use an appropriate method to
determine PEP for a π/4-DQPSK signal and slowly increase/decrease I and Q gain
levels from their nominal set point, as determined by issuing the command ‘cal’.
A step of 100 points (for example, -250 to -150) is approximately equivalent to an
increase of 2dB in power.
