Concepts and Features
R&S
®
ZNC
60
User Manual 1173.9557.02 ─ 13
Similar to this segmentation, ripple limits may be defined in several ranges. The limit lines
(except circle limits) can be stored to a file and recalled. Data or memory traces can be
used to define the segments of an upper or lower limit line. Moreover it is possible to
modify the upper and lower limit lines globally by adding an offset to the stimulus or
response values.
3.4.1.1
Rules for Limit Line Definition
The analyzer places very few restrictions on the definition of limit line segments.
The following rules ensure a maximum of flexibility:
●
Segments do not have to be sorted in ascending or descending order (e.g. the "Start
Stimulus" value of segment no. n doesn't have to be smaller than the "Start Stimu-
lus" value of segment no. n+1).
●
Overlapping segments are allowed. The limit check in the overlapping area is related
to the tighter limit (the pass test involves a logical AND operation).
●
Gaps between segments are allowed and equivalent to switching off an intermediate
limit line segment.
●
Limit lines can be partially or entirely outside the sweep range, however, the limits
are only checked at the measurement points.
The following figure shows a limit line consisting of 3 upper and 2 lower limit line seg-
ments. To pass the limit check, the trace must be confined to the shaded area.
As a consequence of the limit line rules, a DUT will always pass the limit check if no limit
lines are defined.
When the sweep axis is changed from linear frequency sweep to logarithmic sweeps,
straight limit lines are transformed into exponential curves. The sweep points are re-
distributed along the x-axis, so the number of failed points may change.
Operations on Traces
