Anritsu 682XXB, 683XXB 682XXB/683XXB MM 3-49

WIDE FM Mode
1. Set up the 682XXB/683XXB as follows:
a. Reset the instrument by pressing SYSTEM,
then Reset . Upon reset, the CW Menu is dis-
played.
b. Press Edit F1 toopen the current frequency
parameter for editing.
c. Set F1 to 5.0 GHz.
2. Set up the Spectrum Analyzer as follows:
a. CF: 5.0 GHz
b. Span/Div: 100 kHz (1 MHz across the display)
3. On the 682XXB/683XXB, make the following set-
tings:
a. Press MODULATION, then FM . At the re-
sulting FM Status menu, press More togo the
additional FM Status menu.
b. At the additional FM Status menu, press
Wide , then press Previous Menu to return to
the main FM Status menu.
c. At the FM Status menu, press Edit Dev. and
set the deviation for 2.40 rad.
d. Press Edit Rate andset the rate to 99.8 kHz.
e. Press On/Off to turn FM on.
4. On the 682XXB/683XXB, use the cursor control
key to place the cursor under the last 0 in the de-
viation setting (2.40 rad). While observing the
first Bessel null (Figure 3-15), increase/decrease
the FM deviation with the cursor control key to
reduce the carrier as low as possible.
5. Record the FM deviation, displayed on the
682XXB/683XXB, on the TestRecord.
6. Compute the FM accuracy with the following for-
mula:
Accuracy in M Deviation inrad (%) ()
.
=æ
è
çö
ø
÷´
F
240 100
7. The calculated result should be between 93.7%
and 106.3%. Record this result on the TestRe-
cord.
682XXB/683XXB MM 3-49
PERFORMANCE PHASE
VERIFICATION MODULATION TESTS
CENTER FREQUENCY
BESSEL
NULL
Figure 3-15. TypicalSpectrum Analyzer Display
of Bessel Null on MWaveform
NOTE
You may need to adjust the RBW
settingon the Spectrum Analyzer in
order to see the >–48 dBc null.