Rohde & Schwarz 1145.1010.04/05/06, Operating Manual

Page: 270 / 813

Trace Menu R&S
®
ZVA/ZVB/ZVT
1145.1084.12 4.108 E-6
Zero Delay at Marker
Corrects the measurement result by adding or subtracting a constant group delay. This function must be
applied to a trace which is displayed in group delay format. The trace is shifted in vertical direction so
that the delay at the marker position vanishes.
The delay represents the propagation time of the wave across the DUT, so this operation corresponds
to a electrical length compensation, i.e. to a shift of the reference plane by adding to or subtracting from
the test port a simulated lossless transmission line of variable length. The correction must be carried
out on the
Delay trace but has an impact on all trace formats.
A standard application of Zero Delay at Marker is correction of the constant delay caused
by the interconnecting cables between the analyzer test ports and the DUT (line stretch).
The Zero Delay at Marker function modifies the Offset parameters and therefore influences the
entire channel.
Trace - Lines
The commands in the Lines define limits for the measurement results, visualize them in the diagrams
and activate/deactivate the limit check. Besides the menu provides a horizontal line for each trace.
Limit Lines
A limit line is a set of data to specify the allowed range for some or all points of a trace. Typically, limit
lines are used to check whether a DUT conforms to the rated specifications (conformance testing).
•
The upper limit line defines the maximum value for the trace points.
•
The lower limit line defines the minimum value for the trace points.
A limit check consists of comparing the measurement results to the limit lines and display a pass/fail
indication. An acoustic warning and a TTL signal at the USER CONTROL port can be generated in
addition if a limit is exceeded.
Upper and lower limit lines are both defined as a combination of segments with a linear dependence
between the measured quantity and the sweep variable (stimulus variable). The limit lines can be
stored to a file and recalled. Data or memory traces can be used to define the segments of a limit line.
Moreover it is possible to modify the limit lines globally by adding an offset to the stimulus or response
values.