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Concepts and Features
R&S
®
ZNB/ZNBT
207
User Manual 1173.9163.02 ─ 53
is sufficiently above the f
min
, the entire set of sweep points is shifted towards lower
frequencies so that the stop frequency is decreased.
If the start frequency of the sweep is close to f
min
, then the sweep points can have
to be shifted towards higher frequencies. If the last sweep point of the calculated
harmonic grid exceeds the maximum frequency of the analyzer, then an error mes-
sage is displayed, and another harmonic grid algorithm must be used.
●
Keep "Stop Frequency and Approximate Frequency Gap" means that the stop fre-
quency is maintained and the number of sweep points is increased until the range
between f
min
and the stop frequency is filled. The frequency gap is approximately
maintained.
The figures above are schematic and do not comply with the conditions placed on the
number of sweep points and interpolated/extrapolated values.
The harmonic grids cannot be calculated for any set of sweep points. If the minimum
number of sweep points is smaller than 5, then the interpolation/extrapolation algorithm
for additional sweep points does not work. The same is true if the number of sweep
points or stop frequency exceeds the upper limit. Besides, the ratio between the sweep
range and the interpolation range between f = 0 and f = f
min
must be large enough to
ensure accurate results. If the sweep range for the harmonic grid exceeds the fre-
quency range of the current system error correction, a warning is displayed.
Finding the appropriate algorithm
The three types of harmonic grids have different advantages and drawbacks. Note that
for a bandpass transformation the grid parameters have the following effect:
●
A wider sweep range (i.e. a larger bandwidth) increases the time domain resolu-
tion.
●
A smaller frequency gap extends the unambiguous range.
●
A larger number of points increases the sweep time.
Optional Extensions and Accessories