3 Spectrum Analyzer Mode
3.5 ACP Measurement
Mode Measurements Supports Adaptive NFE?
SA SAN Yes
SRCOMMS ACP, CHP, MON, OBW, SEM, SPUR Yes
VMA ACP, CHP, OBW, SEM, SPUR Yes
WCDMA ACP, CHP, MON, OBW, SEM, SPUR Yes
WLAN CHP, MON, OBW, SEM, SPUR Yes
The menus and command options are as follows:
NFE State Modes with
Adaptive NFE
Modes without
Adaptive NFE
SCPI
Off Off Off See "NFE On/Off Command" on
page 1087
On Full On
Adaptive Adaptive n/a See "Adaptive NFE Command" on
page 1088
As shown in the table above, the On state (in Modes that do not support Adaptive
NFE) matches the Full state in Modes that do support Adaptive NFE.
To maintain SCPI backwards compatibility, the existing command to turn NFE on or
off is retained, and a new command is added to set the state to turn AdaptiveON or
OFF:
–
[:SENSe]:CORRection:NOISe:FLOor ON|OFF|1|0 is retained, with the
default changed to ON for Modes that support Adaptive NFE
–
[:SENSe]:CORRection:NOISe:FLOor:ADAPtive ON|OFF|1|0 is added (for
certain Modes), default = ON
When NFE is On or Full, the expected noise power of the instrument (derived from a
factory calibration) is subtracted from the trace data. This will usually reduce the
apparent noise level by about 10dB in low band, and 8dB in high band (>~3.6GHz).
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 the 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
Extension on.
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,
1086 Spectrum Analyzer Mode User's &Programmer's Reference