Anritsu 681XXC - Manual (Page 109)

This menu contains an external FM status window
that shows the current menu selections and the
measured FM Deviation. (The FM deviation meas-
urement function measures the voltage of the exter-
nal modulation signal and calculates the peak
frequency deviation.) This menu lets you perform
the following:
q Turn FM on/off.
q Set the FM sensitivity.
q Select the input impedance (600 W or 50W) of
the input connector.
q Select the input connector (front panel or rear
panel
FM IN ) that is connected to the external
signal source.
Press On / Off to turn FM on and off. Both the FM
status display and FM modulation status area will
reflect your selection.
Press Edit Sens to open the FM Sensitivity pa-
rameter, then edit the current value using the cur-
sor control key or rotary data knob or enter a new
value using the keypad and the appropriate termi-
nator key. The FM Sensitivity range is
±10 kHz/V to
±20 MHz/V for Locked and Unlocked Narrow FM
modes and
±100 kHz/V to ±100 MHz/V for Unlocked
Wide FM mode. To close the open FM Sensitivity pa-
rameter, press
Edit Sens or make another menu se-
lection.
Press 600 W/50W to select the input impedance of
the input connector. The FM status display will
reflect your selection.
Press Front/Rear to select the front or rear panel
FM IN connector. The FM status display will reflect
your selection.
3-76 681XXC OM
LOCAL (FRONT SIGNAL
PANEL) OPERATION MODULATION
ERR
This error message is displayed
when the external FM modulating
signal exceeds the input voltage
range. The message “
Reduce FM
Input Level ” also appears at the bot-
tom of the FM status display. FM is
turned off until the modulating sig-
nal is within the input voltage
range.