3 Short-Range Comms & IoT Mode
3.10 Spurious Emissions Measurement
Remote Command
[:SENSe]:CORRection:NOISe:FLOor:ADAptive ON | OFF | 1 | 0
[:SENSe]:CORRection:NOISe:FLOor:ADAptive?
Example First turn NFE on, this is Full mode
:CORR:NOIS:FLO ON
Then set it to Adaptive
:CORR:NOIS:FLO:ADAP ON
Dependencies Only available in Modes that support Adaptive NFE
Only appears in instruments with the NFE or NF2 license installed. In all others, the control does not
appear, however the SCPI command is accepted without error, but has no effect
Couplings Sending :CORR:NOIS:FLO ON turns NFE Adaptive OFF for backwards compatibility, so to turn
Adaptive on, you must issue the commands in the proper order, as shown in the example above
Preset Not affected by Mode Preset, but set to ON at startup and by Restore Mode Defaults
State Saved No
More Information
The instrument is characterized in the factory (or during a field calibration) with a
model of the noise, referred to the input mixer, versus frequency in each band and
path combination. Bands are 0 (low band) and 1 through 4 (high band) in a 26.5 GHz
instrument, for example. Paths include normal paths, preamp paths, the electronic
attenuator, etc.
In most band/path combinations, the noise can be well characterized based on just
two parameters and the instrument frequency response before compensation for
frequency-dependent losses.
After the noise density at the input mixer is estimated, the effects of the input
attenuator, RBW, detector, etc. are computed to get the estimated input-port-
referred noise level.
In the simplest case, the measured power (signal plus analyzer noise) in each display
point (bucket) is compensated by subtracting the estimated noise power, leaving
just the signal power. This is the operation when the detector is Average, and the
Average Type is set to Power.
In other cases, operation is often not quite as good but still highly effective. With
peak detection, the noise floor is estimated based on the RBW and the duration of
the bucket using the same equations used in the noise marker function. The voltage
of the noise is subtracted from the voltage of the observed signal-plus-noise
measurement to compute the estimated signal voltage. The peak detector is one
example of processing that varies with detector to give good estimates of the signal
level without the analyzer noise.
For best operation, the average detector and the power scale are recommended, as
already stated. Peak detection for pulsed-RF can still give excellent effectiveness.
FFT analysis does not work well, and does not do NFE well, with pulsed-RF signals,
1472 Short Range Comms & IoT Mode User's &Programmer's Reference
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