3 WLAN Mode
3.4 SEM Measurement
not much averaging is being performed, the signal displays more like the NFE-off
case; and when lots of averaging is being performed, the signal displays more like
the full-NFE case.
Adaptive NFE (in Modes that support it) is recommended for general-purpose use.
For fully ATE (automatic test equipment) applications, where the distraction of a
person using the instrument is not a risk, Full NFE is recommended.
NFE works with any RBW, VBW, detector, any setting of Average Type, any amount
of trace averaging, and any signal type. It is ineffective when the trace is not
smoothed (smoothing processes include narrow VBWs, trace averaging, and long
sweep times with the detector set to Average or Peak). It works best with extreme
amounts of smoothing, and with the average detector, with Average Type set to
Power.
In those cases where the cancellation is ineffective, it nonetheless has no
undesirable side-effects. There is no significant speed impact to having Noise Floor
ExtensionON.
The best accuracy is achieved when substantial smoothing occurs in each point
before trace averaging. Thus, when using the average detector, results are better
with long sweep times and fewer trace averages. When using the sample detector,
the VBW filter should be set narrow with less trace averaging, instead of a wide
VBW filter with more trace averaging.
NOTE
Noise Floor Extension has no effect unless the RF Input is selected, therefore it
does nothing when External Mixing is selected.
In Modes that support Adaptive NFE, the default state of NFE is Adaptive. In
Modes that do not support Adaptive NFE, the default state of NFE is OFF. Prior to
the introduction of Adaptive NFE (firmware version A.18.00), the default state of
NFE was OFF for all Modes.
With the introduction of Adaptive NFE, the menu control is changed from On|Off to
Full|Adaptive|Off. For SCPI Backwards Compatibility, the existing SCPI command to
turn NFE on and off was retained, and a new command was added to set the state to
turn Adaptive On and Off
[:SENSe]:CORRection:NOISe:FLOor ON|OFF|1|0 is retained, default changed
to On for modes which support Adaptive NFE
[:SENSe]:CORRection:NOISe:FLOor:ADAPtive ON|OFF|1|0 is added (for
certain Modes), default=On
FULL = :CORRection:NOISe:FLOor ON plus
:CORRection:NOISe:FLOor:ADAPtive ON
Remote Command
[:SENSe]:CORRection:NOISe:FLOor ON | OFF | 1 | 0
[:SENSe]:CORRection:NOISe:FLOor?
WLAN Mode User's &Programmer's Reference 638
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