Keysight Technologies C Series - Relative Limit Lines; Build From Trace

Data Analysis FeaturesDELETE_IF
All about Limit Lines
Keysight N9915-90020 User’s Guide 751
— Press Add then choose from the following:
— Add Point - Adds a blank X/Y data point below the cursor.
—
Add Limit - Adds a default limit line below the current limit.
— Press
Clear then choose from the following:
— Clear Point - Removes the X/Y data point on which the cursor resides.
—
Clear Limit - Removes the limit Line on which the cursor resides.
—
Clear All - Removes ALL limit lines.
— Press <Back
to return to the Limit menu.
Relative Limit Lines
Relative limit lines are X/Y coordinates that are referenced to the center frequency (X-axis) and
acquisition (Y-axis).
Use relative limits to test devices or signals that are identical except for the center frequency or
amplitude. With relative limit lines in place, you change the center frequency of the measurement
and the limits look as though they are in the same location.
The same is true for acquisition. When you expect to measure a different power level, instead of
changing the Y-axis value of all of the fixed limits, simply change to relative limits. The limits will
then remain a constant Y-axis distance from the acquisition.
Each limit line can be changed at any time from Fixed to Relative, and Relative to Fixed.
How to Create a Relative Limit Line
The easiest way to create a Relative limit line is to create a Fixed Limit at a specific center frequency
and acquisition. Learn how “Relative Limit Lines” on page 751. Then change the limit line to
Relative. The X/Y data points will be re-calculated relative to the center frequency and acquisition.
Build From Trace
A limit line can be built from an existing trace. One X/Y point is made from each measured data
point. Then, using an offset value, you can shift the limit line UP for upper limits or DOWN for lower
limits.
Once limit lines have been built from the trace, changes that you make to the trace, such as
frequency range, do NOT change the limits. However, the limit line properties can be edited just like
standard limit lines.