R&S FSW Series, Руководство пользователя

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Common Analysis and Display Functions
R&S
®
FSW
560 User Manual 1173.9411.02 ─ 43
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The entered frequencies or times need not necessarily be selectable in R&S FSW.
A limit line may also exceed the specified frequency or time range. The minimum
frequency for a data point is -200 GHz, the maximum frequency is 200 GHz. For
the time range representation, negative times may also be entered. The allowed
range is -1000 s to +1000 s.
Figure 9-8: Example for an upper limit line
Limits and Margins
Limit lines define strict values that must not be exceeded by the measured signal. A
margin is similar to a limit, but less strict and it still belongs to the valid data range. It
can be used as a warning that the limit is almost reached. The margin is not indicated
by a separate line in the display, but if it is violated, a warning is displayed. Margins are
defined as lines with a fixed distance to the limit line.
To check the signal for maximum levels you must define an upper limit , whereas to
check the signal for minimum levels you must define a lower limit .
Limits can be defined relative to the reference level, the beginning of the time scale, or
the center frequency, or as absolute values.
Relative scaling is suitable, for example, if masks for bursts are to be defined in zero
span, or if masks for modulated signals are required in the frequency domain.
Thresholds
If the y-axis for the limit line data points uses relative scaling, an additional absolute
threshold can be defined for the limit check. In this case, both the threshold value and
the relative limit line must be exceeded before a violation occurs.
Display and Limit Lines