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R&S ZVL
GUI Reference
Trace Menu
Operating Manual 1303.6580.32-06
147
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
frequencies, so that the missing values (green and red dots) are obtained without any additional
input. The extrapolation is repeated after each sweep.
Remote
control:
CALCulate<Chn>:TRANsform:TIME:LPASs KFSTop | KDFRequency |
KSDFrequency
CALCulate<Chn>:TRANsform:TIME:LPASs:DCSParam
CALCulate<Chn>:TRANsform:TIME:LPASs:DCSParam:CONTinuous
CALCulate<Chn>:TRANsform:TIME:LPASs:DCSParam:EXTRapolate
CALCulate<Chn>:TRANsform:TIME:LPFRequency
Set Harmonic Grid
In the
Set Harmonic Grid...
panel of the
Low Pass Settings
dialog, a harmonic grid can be calculated in
three alternative ways:
•
Keep
Stop Frequency and Number of Points
calculates a harmonic grid based on the current stop
frequency
(Channel – Center / Span
–
Stop
)
and the current number of sweep points
(Channel –
Sweep – Number of Points).
This may increase the step width, narrowing the unambiguous range
but improving the time domain resolution.
•
Keep
Frequency Gap and Number of Points
calculates a harmonic grid based on the current stop
frequency
(Channel – Center / Span – Stop)
and the current frequency gap (the spacing between
the equidistant sweep points, i.e. the sweep Span divided by the Number of Points minus one) .
This leaves the unambiguous range unchanged but may lower the stop frequency and therefore
deteriorate the time domain resolution.
•
Keep
Stop Frequency and Approximate Frequency Gap
calculates a harmonic grid based on the
current stop frequency
(Channel – Center / Span – Stop),
increasing the number of points
(Channel – Sweep – Number of Points)
in such a way that
the frequency gap remains
approximately the same. This leaves both the time domain resolution and the unambiguous range