Agilent Technologies 8719ES User Manual page 215

Making Time Domain Measurements
Range
In this example, the range is 100 ns, or 30 meters electrical length. To prevent the time
domain responses from overlapping, the test device must be 30 meters or less in electrical
length for a transmission measurement (15 meters for a reflection measurement). The
analyzer limits the stop time to prevent the display of aliased responses.
To increase the time domain measurement range, first increase the number of points, but
remember that as the number of points increases, the sweep speed decreases. Decreasing
the frequency span also increases range, but reduces resolution.
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