Anritsu 681XXC User Manual
In Unlocked Wide mode, frequency modulation is
accomplished by applying the modulating signal to
the main tuning coil of the YIG-tuned oscillator. Un-
locked Wide FM mode allows maximum deviations
of
accomplished by applying the modulating signal to
the main tuning coil of the YIG-tuned oscillator. Un-
locked Wide FM mode allows maximum deviations
of
±100 MHz for DC to 100 Hz rates.
Providing
Frequency
Modulation
Frequency
Modulation
To provide frequency modulation, first set up the ex-
ternal signal generator, then connect it to either the
681XXC front or rear panel
ternal signal generator, then connect it to either the
681XXC front or rear panel
FM IN
connector.
Next, press
MODULATION
. At the resulting menu
display, press
FM
. The right-most External FM
Status Menu (below) is displayed. Pressing More
brings up the left-most menu.
brings up the left-most menu.
Now, press the menu soft-key
FM Modes
. The third
External FM Status Menu (below) is displayed.
This menu lets you select the FM operating mode.
Press
Locked LN
to select the Locked Low-Noise
FM operating mode; Press
Locked
to select the
Locked FM operating mode; press
Unlocked Narrow
to select the Unlocked Narrow FM operating mode;
or press
or press
Unlocked Wide
to select the Unlocked
Wide FM operating mode. The FM status display
will reflect your selection.
will reflect your selection.
Press
Previous Menu
to return to the main Exter-
nal FM Status Menu display (next page).
681XXC OM
3-75
LOCAL (FRONT
SIGNAL
PANEL) OPERATION
MODULATION
UNLOCKED
When Unlocked Narrow FM or Un-
locked Wide FM is selected ON, this
warning message is displayed on all
menu displays to remind the opera-
tor that the carrier frequency is not
phase-locked.
locked Wide FM is selected ON, this
warning message is displayed on all
menu displays to remind the opera-
tor that the carrier frequency is not
phase-locked.