R&S FSMR, Operating Manual, Page: 193 / 955

R&S FSMR Measurement Receiver Mode
1166.3363.12 4.4-37 E-2
REFERENCE
VALUE
The REFERENCE VALUE softkey defines the frequency or
phase deviation (FM/PM) or the modulation depth (AM) on the
reference line of the y axis. The reference value is set
separately both for each FM, PM and AM signal display and for
the AF spectrum display of the FM, PM and AM signal.
FM signal display:
The reference value allows you to take into account individual
frequency offsets in the trace display (while the
AF COUP
AC/DC softkey permits automatic correction by the average
frequency offset of the signal).
The settable value range is 0 MHz to
±
10 MHz. The softkey is
not available if the AF COUP AC function is active.
AF spectrum display of the FM signal:
In the default setting, the reference value defines the FM
deviation at the top edge of the diagram.
The settable value range is 0 MHz to 10 MHz.
PM signal display:
The reference value allows you to take into account individual
phase offsets in the trace display (while the
AF COUP AC/DC
softkey permits automatic correction by the average phase
offset of the signal).
The settable value range is 0 rad to
±
10000 rad. The softkey is
not available if the AF COUP AC function is active.
AF spectrum display of the PM signal:
In the default setting, the reference value defines the PM
deviation at the top edge of the diagram.
The settable value range is 0 rad to 10000 rad.
AM signal display:
The settable value range is 0% to
±
10000%.
AF spectrum display of the AM signal:
In the default setting, the reference value defines the
modulation depth at the top edge of the diagram.
The settable value range is 0% to 10000%.
IEC/IEEE bus command:
DISP:WIND:TRAC:Y:RVAL 0HZ
COUPLING
AC DC
The COUPLING AC/DC softkey controls the automatic
correction of the frequency offset and the phase offset of the
input signal.
FM signal display:
If
DC is selected, the absolute frequency offset is displayed, i.e. an
input signal shifted with respect to the center frequency is
displayed as not symmetrical to the zero line.
However, if
AC is selected, the frequency offset is automatically
corrected, i.e. the trace is always displayed as symmetrical to
the zero line.
PM signal display:
If DC is selected, the phase drifts off, depending on the frequency
offset that is present. Moreover, the DC signal has a phase offset
of ±
V .
However, if AC is selected, the frequency and phase offset is
automatically corrected, i.e. the trace is always displayed as
symmetrical to the zero line.
The softkey is not available if the FM or PM signal is displayed
in the AF spectrum.
IEC/IEEE bus command
SENS:ADEM:AF:COUP DC