Keysight x-series User Manual

3 Spectrum Analyzer Mode
3.2 Swept SA Measurement
limitations of the digital IF, to a 24 step per decade series from 1 Hz through 3 MHz,
plus the 4, 5, 6 and 8 MHz settings.
For Gaussian filters, the annotation at the bottom of the screen shows the filter
bandwidth type (unless it is Normal) parenthetically between the words “Res BW”
and the value, for example:
Res BW 10.0 Hz (Normal bandwidth)
Res BW (Impulse) 14.8 Hz (Impulse bandwidth)
Flattop filters
When the Flattop filter type is chosen, a new set of 134 RBW hardware settings are
available. These settings realize filters that are approximately rectangular in shape.
When this shape is chosen the filter bandwidth options are irrelevant and therefore
unavailable.
The annotation at the bottom of the screen shows that the Flattop shape is being
used, for example:
Res BW (Flattop) 10 Hz
RBW Filter BW
Selects the type of filter bandwidth used to specify the width of the Gaussian RBW
filters. Historically, the Gaussian Res BW filters in HP/Agilent/Keysight spectrum
analyzers were specified using the –3 dB bandwidth of the filter. That is, a 10 MHz
Res BW filter was a Gaussian shape with its –3 dB points 10 MHz apart. For certain
types of applications, it can be useful to specify the filter width using points other
than the –3 dB points. In the X-Series, the RBW Filter BW function lets you pick the
filter based on its –3 dB (Normal) bandwidth, its –6 dB bandwidth, its Noise
bandwidth, or its Impulse bandwidth. Note that in all four cases the –3 dB
bandwidth is the same. The filter does not change, but the way you specify it
changes.
Example
Set Res BW to 1.0kHz with RBW Filter BW set to Normal. Now, set RBW Filter BW
to –6dB. The bandwidth displayed for Res BW changes to 1.41kHz. The shape and
bandwidth of the filter have not changed, only the way the filter is annotated and the
value that appears in the Res BW active function area have.
Filter BW SCPI Example Displayed bandwidth of a filter with 1kHz –3dB
bandwidth
-3 dB
(Normal)
:BAND:TYPE DB3 1.0 kHz
–6 dB :BAND:TYPE DB6 1.41 kHz
Spectrum Analyzer Mode User's &Programmer's Reference 255

Keysight x-series Specifications

General

Analysis Bandwidth	Up to 1 GHz (depending on model)
Real-Time Bandwidth	Up to 1 GHz (depending on model)
Form Factor	Benchtop
Connectivity	LAN, USB, GPIB
Resolution Bandwidth	1 Hz to 10 MHz (depending on model)