R&S ZVL
GUI Reference
Channel Menu
Operating Manual 1303.6580.32-06
224
Standards
list whenever the selected calibration type requires a
Match.
A click on the node
expands the check boxes for the different positions of the load element. The number of different
positions is defined in the
User Interface
tab of the
System Configuration
dialog.
The sliding match is a one-port standard consisting of an air line with a movable, low-reflection load
element (sliding load). This standard is used because a no perfect match is available over a wide
frequency range. However, a series of measurements at a given frequency with equal mismatch
and varying phase yields reflection factors that are located on a circle in the Smith chart. The
center of this circle corresponds to perfect match. The network analyzer determines and further
corrects this match point following I. Kása's circle-fitting algorithm.
To obtain the reflection coefficient for a perfectly matched calibration standard, the sliding load
must be measured at least at 3 positions which should be unequally spaced to avoid overlapping
data points. Increasing the number of positions to 4 – 6 can improve the accuracy. Moreover it is
recommended to use the predefined load positions of the standard.
The calibration is valid
(Apply
is available) if either the match or three positions of the sliding match
have been measured. However, it is often desirable to acquire calibration data from both standards.
The analyzer combines the data in an appropriate manner:
•
The match results are used up to the lower edge of the specified frequency range of the
sliding match (Min Freq).
•
The sliding match results are used for frequencies above the Min Freq. In general, the
sliding match will provide better results than the match within its specified frequency range.
Checking one of the boxes in the list
causes the analyzer to stop the measurement in all channels except
the active one and measure the standard according to the active channel settings. The progress of the
calibration sweep and the result can be monitored in the diagram. In case of an error (e.g. if the
measurement result shows that the calibration standard was not connected properly),
Abort Sweep
immediately terminates the sweep.
When the sweep is completed, a green checkmark appears in the checkbox. Measurements can be
repeated as often as desired. Newer results overwrite older measurement data.
Most channel settings remain valid for calibration sweeps.
Checks for the calibration sweep
If the sweep range of the active channel exceeds the validity range of the standard model (defined by
Min
Freq
and
Max Freq
in the
Add/Modify Standard
dialog) the analyzer displays a notice box (confirm with
OK).
The dialog provides further controls:
•
Show Measurement Diagram
displays or hides the diagram to the right of the list of Measured
