R&S FSMR, Operating Manual

Page: 223 / 955

R&S FSMR Analyzer - Bandwidths and Sweep Time
1166.3363.12 4.8-7 E-1
SPAN /RBW
MANUAL
The SPAN/RBW MANUAL softkey activates the manual input of
the coupling ratio.
The span / resolution bandwidth ratio can be set in the range
1 to 10000.
IEC/IEEE-bus command
SENS:BAND:RAT 0.1
This setting is only effective for the RBW AUTO selection in the
main menu.
DEFAULT
COUPLING
The DEFAULT COUPLING softkey sets all coupled functions to the default state
( AUTO) . In addition, the ratio RBW/VBW is set to SINE [1/3] and the ratio
SPAN/RBW to 50 in the COUPLING RATIO submenu (default setting, COUPLING
RATIO softkey not highlighted).
IEC/IEEE-bus command
SENS:BAND:AUTO ON
SENS:BAND:VID:AUTO ON
SENS:SWE:TIME:AUTO ON
FILTER
TYPE
The FILTER TYPE softkey opens the selection list for different filter types . In the
range up to 30 kHz digital band filters with Gaussian characteristic and filtering with
FFT algorithm can be selected.
FILTER TYPE
NORMAL (3dB)
FFT
CHANNEL
RRC
NORMAL(3dB) The resolution bandwidths are implemented by Gaussian filters
with the set 3 dB bandwidth and correspond approximately to the
noise bandwidth. For bandwidths up to 100 kHz, digital bandpass
filters are used.
FFT An FFT is performed. For that purpose, the filtered IF signal is
digitized and then transformed into the spectral domain via FFT.
The transformation range depends on the selected filter
bandwidths and can be set between 4 kHz to 50 kHz. If the span is
larger than the transformation range, several transformations are
performed and the results are appended to each other in the
spectral domain.
If the span is smaller than the transformation range, the
measurement results are interpolated when the number of
measurement points provided by the FFT is smaller than the
number of display points in x-direction (625). A flattop window
serves as a window in the time domain so that high amplitude
precision with good selection is achieved.A flat-top window serves
as a window in the time domain so that high amplitude accuracy as
well as good selection are achieved.