6Measurement Of The Am Modulation Depth - Rohde & Schwarz R&S FSP Series Operating Manual

R&S FSP
CHANNEL The CHANNEL BANDWIDTH softkey opens a window for selecting the measure-
BANDWIDTH ment channel bandwidth.
The default setting is 14 kHz.
The specified channel bandwidth allows the optimal setting of the measurement
parameters of the R&S FSP using ADJUST SETTINGS.
Remote command:
ADJUST The ADJUST SETTINGS softkey adapts the span to the channel bandwidth
SETTINGS selected.
For the carrier/noise ratio measurement, the span is set to:
The adjustment is performed once; if necessary, the setting can be changed later
on.
Remote command:
4.5.13.6 Measurement of the AM Modulation Depth
MODULATION The MODULATION DEPTH softkey switches on the measurement of the AM modu-
DEPTH
lation depth. An AM-modulated carrier is required on the screen for ensuring correct
operation.
The level value of MARKER 1 is taken as the carrier level. When this function is acti-
vated, MARKER 2 and MARKER 3 are automatically set symmetrically to the carrier
on the adjacent peak values of the trace as delta markers and MARKER 2 is acti-
vated for the entry.
When the position of MARKER 2 (delta) is changed, MARKER 3 (delta) is moved
symmetrically with respect to the reference marker (MARKER 1).
If the data entry is activated for MARKER 3 (MARKER 1 2 3 4 softkey), the latter can
be moved for fine adjustment irrespective of MARKER 2.
The R&S FSP calculates the power at the marker positions from the measured lev-
els. The AM modulation depth is calculated from the ratio between the power values
at the reference marker and at the delta markers. When the powers of the two AM
side bands are unequal, the mean value of the two power values is used for AM
modulation depth calculation.
4.116
4 × channel bandwidth + measurement margin
SENS:POW:ACH:BWID 14kHz
SENS:POW:ACH:PRES CN | CN0
Operating Manual 1164.4556.12 - 06
Instrument Functions
Analyzer Mode