Anritsu 682XXB - Manual (Page 163)

When the DAC has been completely adjusted,
the program will exit to the
$
prompt.
g. Record step completion on the Test Record.
2. Internal Wide FM Mode Sensitivity calibration is
accomplished by adjusting the FM Variable Gain
Control DAC to reduce the carrier level as low as
possible at frequencies of 5 GHz and 20 GHz. The
modulating signal input is from the internal
Function Generator.
Perform the calibration as follows:
a. At the
$
prompt, type:
calterm 151
and
press <ENTER>.
b. On the Spectrum Analyzer, set the Span/Div to
50 kHz per division.
c. On the computer keyboard, use the ‘, 1, 2, and
3 keys to increment and the 7, 8, 9, and 0 keys
to decrement the value of the DAC’s setting.
Start calibration by pressing an increment key.
d. While observing the first Bessel null (Figure
4-16) on the Spectrum Analyzer display, adjust
the value of the DAC’s setting to reduce the
carrier level as low as possible.
e. When finished setting the DAC, press
Q
on the
keyboard to go to the next calibration step.
When the DAC has been completely adjusted,
the program will exit to the
$
prompt.
f. Record step completion on the Test Record.
3. Wide FM Mode Flatness calibration is accom-
plished by adjusting the
FM Flatness DAC to re-
duce the carrier level as low as possible for
sensitivity settings of 2.4 Rad/V and 14.9 Rad/V
at 5 GHz. The modulating signal input is from
the external Function Generator.
Perform the calibration as follows:
a. At the
$
prompt, type:
calterm 155
and
press <ENTER>.
b. Set up the Function Generator for a 400 Hz
sine wave with an output level of 0.707 volts
RMS (2 volts peak to peak). Use a frequency
counter to verify the output frequency of your
function generator is set to
±1%.
682XXB/683XXB MM 4-53
PHASE MODULATION
CALIBRATION (
FM) CALIBRATION
NOTE
To save the calibration data after
completing any calibration step,
type:
calterm 787
and press
<ENTER>.
NOTE
You may need to adjust the RBW
setting on the Spectrum Analyzer in
order to see the >–40 dBc null.