Common Measurement Settings
R&S
®
FSPN
113
User Manual 1179.4363.02 ─ 01
The minimum RBW can be set to 0.0003% (instead of 0.1%) if this function is enabled.
Also, only one measurement channel can be used due to memory limitation.
Be aware that if the function is enabled, and the function is enabled in an instrument
saveset, recall of the saveset fails. If the function is enabled in a saveset used for
startup recall, every second preset acts as if startup recall had been disabled.
If this function is enabled and RBWs below 0.1% are used, the estimated
Remote command:
[SENSe:]LIST:BWIDth[:RESolution]:USMall
Defining cross-correlation parameters
Cross-correlation is a method to calculate the noise characteristics by routing it through
two different signal paths. The signal has correlated noise characteristics in both chan-
nels while the oscillators have uncorrelated noise characteristics. Through cross-corre-
lation operations, the noise of the DUT is kept constant while the noise of the signal
path is reduced.
You can define a custom number of cross-correlation operations for each half decade,
or let the application select an appropriate number, depending on the "Half Decade
Config" mode.
For an
automatic selection
, the number of cross-correlation operations that are per-
formed depends on the half decade that is measured. Small offsets (which usually
have a higher noise level) require fewer operations to get accurate results, while large
offsets (whose noise levels can be very low) require more operations for accurate
results.
The base number of the first decade is a fixed value. The number of operations for the
other half decades is determined in such a way, that all operations are finished at
roughly the same time.
Example:
The operations in the first half decade need 1
s to finish. The number of operations
done in the other half decades is calculated with respect to this 1
s timeframe. For
example, if the application can perform 10 cross-correlation operations in 1
s in
another half decade, it will do so, but no more than that number.
You can control the number of cross-correlations for the first half decade with the
cross-correlation factor ("XCORR Factor"). By multiplying this value with the base num-
ber of operations for the first half decade, the application calculates the time it takes to
perform these operations in the first half decade and then adjusts the number of opera-
tions for all other half decades.
When you turn on the "XCORR Optimization" feature, cross-correlation operations are
only performed as long as the measurement results still improve. When this is not the
case, the R&S
FSPN stops calculating results, even when the selected number of
operations has not yet been reached. This is thus a good tool to speed up the mea-
surement.
Noise Measurement Configuration
