Concepts and Features
R&S
®
ZNB/ZNBT
96
User Manual 1173.9163.02 ─ 38
●
Trace segments with a shape that is characteristic for bandpass or bandstop filters
(bandfilter search); see
When the search is activated, the active marker is moved to the (next) point that meets
the search criteria. If the trace contains no markers, a marker M1 is created and used
for the search. The search result is displayed in the marker info field. If no search result
can be found, the marker remains at its original position.
Some search functions can be activated repeatedly in order to find all possible search
results. Moreover the analyzer provides a "Tracking" mode where the search is repea-
ted after each sweep.
Multiple Peak Search
Multiple peak search allows to find multiple local minima/maxima at once. Markers 1 to
10 are assigned to the peaks detected from the start frequency towards the stop fre-
quency. Multiple Peak Search uses its own search and tracking settings; search and
tracking settings for standard marker search are ignored.
Bandfilter Search
In a bandfilter search, the R&S
ZNB/ZNBT locates trace segments with a bandpass or
bandstop shape and determines characteristic filter parameters.
Bandpass and bandstop regions can be described with the same parameter set:
●
A bandpass region contains a local maximum around which the magnitude of the
trace falls off by more than a specified value.
●
A bandstop region contains a local minimum around which the magnitude of the
trace increases by more than a specified value.
The analyzer locates bandpass and bandstop regions and determines their position
("Center" frequency) and shape ("Bandwidth", "Lower Edge" and "Upper Edge", quality
factor. For a meaningful definition of the bandwidth factor, the trace format must be "dB
Mag" .
The info field contains the following search results:
●
"Bandwidth" is the n-dB bandwidth of the bandpass/bandstop region, where n is a
selectable bandwidth factor. The bandwidth is equal to the difference between the
lower and the upper band edge frequency.
●
"Center" is calculated as the geometric or arithmetic mean of the lower band edge
frequency f
LBE
and the upper band edge frequency f
UBE
:
f
Center
= sqrt (f
LBE
* f
UBE
)
(geometric mean) or
f
Center
= 1/2 (f
LBE
+ f
UBE
)
(arithmetic mean)
The arithmetic mean is always higher than the geometric mean. The values are
close if the bandwidth is small compared to the geometric mean of the band edges.
Screen Elements
