How To Modify The I/Q Data Measurement Parameters; Adjusting The Bandwidth Settings - Keysight A Series User Manual

IQ Analyzer (IQA) – Option 351 (CPU2 Only)
I/Q Analyzer (IQA) Mode Settings

How to modify the I/Q data measurement parameters

The following sections assume you have already selected your I/Q data
measurement type (i.e., Spectrum, Waveform (RF Envelope or I/Q Waveform),
or User Defined).
This section contains the following:
"Adjusting the Bandwidth Settings" on page 305
"Changing between the Continuous and Single captures and
adjusting the Trigger settings" on page 307
"Adjusting the Measurement Setup Settings" on page 310
"Adjusting the Trace Settings" on page 310
"Adjusting the Frequency Settings" on page 312
"Adjusting the Scale and Amplitude Settings" on page 312
"Preamplifier Control (Opt 235)" on page 314

Adjusting the Bandwidth Settings

— Press BW 2.
— Then choose from the following:
There is a significant difference between resolution BW in FFT
measurements and the resolution BW of a traditional "sweeping"
spectrum analyzer (SA) measurement. The resolution BW in FFT
measurements does not directly control the IF BW like a traditional SA
swept measurement. Resolution bandwidth is directly related to the
analysis length (window) and or data acquisition capture length (sweep
time).
Keysight N9927-90020 User's Guide
— Res BW (Spectrum only) – Sets the resolution bandwidth of the FFT
analysis. Changing this value changes the FFT window size, analysis
length, and the sweep time (data acquisition capture length). This
softkey is only available when IQA is set to Spectrum (Freq Domain).
When the resolution bandwidth value is set to Auto (default) the
FieldFox automatically sets the optimum resolution bandwidth value.
(Default: 200 kHz, Minimum: 0.1 Hz, maximum: 3 MHz).
— Analysis Length Sets the FFT analysis length that is the length of the
complex I/Q data points (I/Q–pairs) vector that is used for spectrum
analysis, expressed in the number of samples. (Couplings: In Auto,
this setting is directly coupled to the Res BW and to Span. Minimum:
8, Maximum: 524,288. Where each FFT length "point" is equal to 1 I
and 1 Q point. So, 237 is equal to 237 I and 237 Q points).
305