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Interference Analyzer (Option 25) 3-19 Limit Menu
Spectrum Analyzer MG PN: 10580-00349 Rev. M 3-87
Limit Envelope Menu
Key Sequence:
Shift > Limit
(
6
) key
> Limit Envelope
Create Envelope: Press this submenu key to generate the envelope using
the Limit Envelope characteristics. If the default results are not satisfactory,
then you can make adjustments to the amplitude and frequency of each
inflection point, and you can add or delete inflection points.
Update Envelope Amplitude: While working on your envelope (or if your
signal amplitude changes), you may want to adjust the amplitude of the
current limit without changing the frequencies of the inflection points.
Pressing this submenu key makes those amplitude adjustments without
frequency adjustments.
Upper Points (if Upper Limit is selected)
Lower Points (if Lower Limit is selected) : Use this submenu key to define
how many inflection points you want for the selected upper or lower limit
envelopes. The value can be between 2 and 41, but must be an even number
when a Square Upper Shape is selected (below). Note that the upper and
lower limit lines do not need to have the same number of points.
Upper Offset (if Limit is toggled to Upper)
Lower Offset (if Limit is toggled to Lower) : This submenu key is used to
define how far away from the measured signal the upper or lower envelope
will be placed. The limits are ±100 dB. For an upper envelope, usually the
value will be positive in order to place the envelope above the signal. For a
lower envelope, the value will usually be negative in order to place the
envelope below the signal.
Upper Shape (if Limit is toggled to Upper)
Lower Shape (if Limit is toggled to Lower) : Press this submenu key to
choose whether the default for the upper or lower envelope will be with flat
tops (Square setting) and reasonably vertical lines to change level or whether
the envelope will have sloped lines (Slope setting) between adjacent
inflection points. When the square envelope type is selected, two inflection
points are used for each horizontal segment. You can toggle between a
square envelope and a sloped envelope by pressing this submenu key.
Figure 3-82 is an example of a Square Limit Envelope.
Back: Press this submenu key to return to the “Limit Menu” on page 3-83 .
Figure 3-81. IA Limit Envelope Menu
Upper Shape
Square Slope
Limit Envelope
Back
Create Envelope
Update
Envelope Amplitude
Upper Points
21
Upper Offset
3.0 dB