Concepts and Features
R&S
®
ZNC
100
User Manual 1173.9557.02 ─ 13
Table 3-10: Properties of frequency windows
Window
Sidelobe suppres-
sion
Relative impulse
width
Best for...
No Profiling (Rect-
angle)
13 dB
1
–
Low First Sidelobe
(Hamming)
43 dB
1.4
Response resolution: separation of closely
spaced responses with comparable ampli-
tude
Normal Profile
(Hann)
32 dB
1.6
Good compromise between pulse width
and sidelobe suppression
Steep Falloff (Boh-
man)
46 dB
1.9
Dynamic range: separation of distant
responses with different amplitude
Arbitrary Sidelobes
(Dolph-Chebychev)
User defined
between 10 dB and
120 dB
1.2 (at 32 dB side-
lobe suppression)
Adjustment to individual needs; tradeoff
between sidelobe suppression and
impulse width
3.7.1.4
Harmonic Grid
A harmonic grid is formed by a set of equidistant frequency points f
i
(i = 1...n) with spacing
Δf and the additional condition that f
1
= Δf. In other words, all frequencies f
i
are set to
harmonics of the start frequency f
1
.
If a harmonic grid, including the DC value (f = 0), is mirrored to the negative frequency
range, the result is again an equidistant grid.
The point symmetry with respect to the DC value makes harmonic grids suitable for low-
pass time domain transformations.
Visualization of the harmonic grid algorithms
The R&S ZNC provides three different algorithms for harmonic grid calculation. The three
harmonic grids have the following characteristics:
●
Keep "Stop Frequency and Number of Points" means that the stop frequency and the
number of sweep points is maintained. The sweep points are re-distributed across
the range between the minimum frequency of the analyzer and the stop frequency;
the step width may be increased.
●
Keep "Frequency Gap and Number of Points" means that the number of sweep points
and their relative spacing is maintained. If the start frequency of the sweep is suffi-
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