Analyzer R&S
UP300/350
E-1147.2759.00
6-254
Operating Manual, 11/2007
You can select an FFT window from the following selection of window
functions:
Rectangular
If the signal fits in the section for the FFT exactly with an integer multiple
of periods, there is no discontinuity at the section boundaries, and then a
window is not required and the maximum frequency resolution is
possible.
Hamming
This window does not provide any significant advantages; it was
implemented simply to complete the range.
Hann
This window combines selectivity with good leakage suppression in the
"far-off range" but has a relatively wide bell-shaped curve around the
signal lines.
Blackman Harris
The slope of the bell-shaped curve up to approx. 80 dB is very steep;
however, this window has considerable "leakage" for values under
80 dB.
Rife Vincent 1
Rife Vincent 2
Rife Vincent 3
The suppression of far-off interference is very good for all 3 windows.
The width of the bell-shaped curve at the bottom of the individual lines
drops and the width at the top increases as the Rife Vincent number
increases. It is therefore possible to set various compromises between
frequency resolution and the suppression of adjacent lines.
Flat Top
Here, the region around the carrier is deliberately distorted to such an
extent that at least two adjacent lines (in the case of excitation with one
sinewave line only) always have roughly the same magnitude.
Advantage:
Unlike other window functions, the amplitude can be read
off accurately from the graph.
Disadvantage:
The frequency selectivity is poor.
Kaiser (
β
= 12)
With this window, the compromise between selectivity, sideband
suppression and suppression of far-off interference is good
Note:
The setting is always valid for both channels (Ch 1&2).
Selecting the
FFT window
1.
Press the
function key
in the
menu.
A selection field containing the available settings is displayed. The
default setting is “Rife Vincent 2“.
2.
Use the
rotary knob
[11] to select a setting.
3.
Press the
ENTER key
[5] to close the selection field.
The new setting is stored and displayed in the parameter field.
Ch 1&2
Summary of Contents for Smart Instruments UP300
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