Dtf Measurement Calculations - Anritsu MS2024B Manual

Field Measurements

DTF Measurement Calculations

Fault Resolution
Fault resolution is the ability of the system to separate two closely spaced discontinuities. If
the fault resolution is 10 feet and two faults are 5 feet apart, then the VNA Master will not be
able to show both faults unless Fault Resolution is improved by widening the frequency span.
DMax
DMax is the maximum horizontal distance that can be analyzed. The Stop Distance can not
exceed Dmax. If the cable is longer than Dmax, then Dmax needs to be improved by
increasing the number of datapoints or by lowering the frequency span (ΔF). Note that the
datapoints can be set from 1 to 4001.
Suggested Span
If the frequency span is set to the suggested span, the Stop Distance will equal Dmax giving
the best fault resolution for the given conditions. With Stop Dist entered in meters, the
following relationship can be obtained:
Vector Network Analyzer MG
Fault Resolution (m)
(
=
D
Datapoints 1
max
Suggested Span (Hz)
PN: 10580-00289 Rev. K
8
× ×
1.5 10 vp
=
--------------------------------- -
ΔF
) ×
– Fault Resolution
( Datapoints 1 )
–
= ------------------------------------------------------------------------------------------- -
Stop Distance (meters)
5-9 Distance-To-Fault (DTF)
8
× ( )
× ×
1.5 10 vp
5-17