Trace Menu R&S
®
ZVA/ZVB/ZVT
1145.1084.12 4.66 E-6
The dialog can be used to change the present grid of sweep points, which may or may not be harmonic.
• The three buttons in the Set Harmonic Grid... panel provide alternative algorithms for
calculation of a harmonic grid, based on the current sweep points.
• The control elements in the DC Value panel define the measurement result at zero frequency
and in the interpolation/extrapolation range between f = 0 and f = f
min
. They are enabled after a
harmonic grid has been established.
Defining the low frequency sweep points
After calculating a harmonic grid, the analyzer must determine the value of the measured quantity at
zero frequency and possibly at additional points in the range between f = 0 and f = f
min
.
The following figure shows a scenario where the harmonic grid was calculated with fixed Stop
Frequency and Number of Points. The DC value and the values at the two additional red points must be
extrapolated or interpolated according to the measured sweep points (blue dots) and the properties of
the DUT.
• If the properties of the DUT at f = 0 are sufficiently well known, then it is recommendable to
enter the DC value manually (Manual Entry) and let the analyzer calculate the remaining values
(red dots) by linear interpolation of the magnitude and phase(Examples: At f = 0 the reflection
factor of an open-ended cable is 1. It is –1 for a short-circuited cable and 0 for a cable with
matched termination. If a cable with known termination is measured, then these real numbers
should be entered as DC values. ).Clicking the Extrapolate button will initiate an extrapolation of
the measured trace towards f = 0 and overwrite the current DC value. This can be used for a
consistency check.
• Continuous Extrapolation initiates an extrapolation of the measured trace towards lower
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