Specifications

Chapter 2 19
Measuring Multiple Signals
Resolving Signals of Equal Amplitude
Measuring Multiple Signals
As the resolution bandwidth is decreased, resolution of the individual
signals is improved and the sweep time is increased. For fastest
measurement times, use the widest possible resolution bandwidth.
Under factory preset conditions, the resolution bandwidth is “coupled”
(or linked) to the span.
Since the resolution bandwidth has been changed from the coupled
value, a # mark appears next to Res BW in the lower-left corner of the
screen, indicating that the resolution bandwidth is uncoupled. (For
more information on coupling, refer to the
Auto Couple key description
in the Agilent Technologies ESA Spectrum Analyzers
User’s/Programmer’s Reference Guide and the PSA Spectrum
Analyzers User’s/Programmer’s Reference Guide.)
NOTE To resolve two signals of equal amplitude with a frequency separation
of 200 kHz, the resolution bandwidth must be less than the signal
separation so a resolution bandwidth of 100 kHz must be used. (For
analyzers that use a 1-3-10 RBW step sequence, a 100 kHz RBW is the
best choice for signal separation, but for high performance analyzers,
like the PSA, a 180 kHz RBW can be selected by fine tuning the RBW
filters at 10% increments.) Filter widths above 200 kHz exceed the
200 kHz signal separation and would not resolve the signals.