Agilent Technologies 8719D User Manual page 405

Windowing improves the dynamic range of a time domain measurement by altering the
frequency domain data prior to converting it to the time domain, producing an impulse
stimulus that has lower sidelobes This makes it much easier to see time domain responses that
are very different in magnitude. The sidelobe reduction is achieved, however, at the expense of
increased impulse width. The effect of windowing on the step stimulus (low pass mode only) is
a reduction of overshoot and ringing at the expense of increased rise time.
the selection of three window types (see lhble B-10).
window
Normal
Maximum
impulse width. The bandpass impulse sidelobe levels are the same as low pass impulse sidelobe levels.
Choose one of the three window shapes listed in 'Ihble 6-10. Or you can use the knob to select
any windowing pulse width (or rise time for a step stimulus) between the softkey values. The
time domain stimulus sidelobe levels depend only on the window selected.
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A window is activated only for viewing a time domain response, and does not affect a
displayed frequency domain response. F'igure 6-72 shows the typical effects of windowing on
the time domain response of a short circuit reflection measurement.
Low pass
is essentially no window. Consequently, it gives the highest
sidelobes.
(the preset mode) gives reduced sidelobes and is the mode
most often used.
window gives the minimum sidelobes, providing the
greatest dynamic range.
rise time) different from the standard window values.
-21 dB
Appliwtion and Operation Concepts
6-131