VNA concepts and features
R&S
®
ZNL/ZNLE
301
User Manual 1178.5966.02 ─ 19
distance between the reference plane and the fault can then be calculated from the
propagation time, accounting for the electrical properties of the transmission line.
Moreover it is possible to define the peaks to be considered as being caused by a fault.
The following example shows the reflection at the end of a faultless open cable con-
nected to test port 2. A full one-port calibration ensures that the distance is measured
from the test port position (reference plane = distance zero). The horizontal position of
marker "M2" corresponds to the cable length of 1417
mm, the additional peak at posi-
tion "M1" is due to a bad connection between the cable and the test port.
Adjust the frequency sweep to the length of the transmission line and the expected dis-
tance to fault:
●
The maximum distance that can be measured is proportional to the number of
sweep points. The larger the number of sweep points, the longer the maximum dis-
tance between the calibrated reference plane and the fault to be located.
●
The maximum distance that can be measured is inversely proportional to the fre-
quency span. The smaller the frequency span, the longer the maximum distance
between the calibrated reference plane and the fault to be located.
However, a smaller frequency span comes at the cost of a coarser distance resolu-
tion.
The R&S
ZNL/ZNLE can automatically determine a suitable number of sweep points
for a given maximum distance to fault ("Auto Number of Points"). Moreover it is possi-
Optional extensions and accessories