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To
select a window, press
($GG)
~~~~~~;~~E~;
.%HMW.
A menu is presented that allows
the selection of three window types (see
‘lhble
6-12).
able
6-12. Impulse Width,
Sidelobe
Level, and Windowing Values
Window
ImpnlSe
Low
Pass
SkP SbP
Type
Sidelobe
llUpUlSC3
Sidelobe
mseThe
Level
Width (50%)
Level (10 - 90%)
Minimum
-13dB
O.bO/Freq
Span
-21
dJ3
0.45IFreq
Span
Normal
-44dB
0.9WFreq
Span
-60
dB
OXWFreq
Span
Maximmn
-75
dB
139/Freq
Span
-70
dB 1
AS/Freq
Span
NOTE: The
bandpass
mode simulates an impulse
stimuli.
Bandpass
impulse width is twice that of low pass
impulse width. The bendpass impulse
sidelobe
levels are the same as low pass impulse
sidelobe
levels.
Choose one of the three window shapes listed in
Table
6-12. 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.
,;
/:,.,,*,
..:::.:..
_
_
,....
.;
,.,..,..,.._
..,
~~~~~
is essentially no window. Consequently, it gives the highest
sidelobes.
~~~
(the preset mode) gives reduced sidelobes and is the mode
most often used.
.‘“...:.:.:...:
/
..:.:.:.:.:...;~..:
_
,.,...
:
/
,.
. . . . .
,,
;fJqjgfmi
window gives the
minimum sidelobes, providing the
greatest dynamic range.
..,,..,.,,.....,.,.,.,,
:..::
. .
..“...:,::::::::::.:::::::::...:.:.,::::::..,..::::.
.”
:::,:,
‘::::::...:,~,.:...~,.:
,,
;..
:.
,,
~~~~~~~~~~~~~~~~~~~~~~~
remembers a user-specified
WindoW
pulse Width (or
step
.:...
.:::........:
u;;....
.A....
.v;
. . . . . . .
.w;
.A....
.;:.w;:
.A..
ci
ii
>;;:..
.A..
.w;;.i..:
:...
rise time) different from the standard window
values.
A window is activated only for viewing a time domain response, and does not affect a
displayed frequency domain response. Figure 6-72 shows the typical effects of windowing on
the time domain response of a short circuit reflection measurement.
Application and Operation Concepts 6-137