R&S ZNB Series User Manual page 235

®
R&S ZNB/ZNBT
4.7.3 Distance-to-fault measurements
Option R&S ZNB-K3 / R&S ZNBT-K3
With option K3 "Distance-to-Fault", the R&S ZNB/ZNBT can locate faults and disconti-
nuities on cables and transmission lines.
Faults produce peaks on the impulse response (in the time domain) that is calculated
from the measured reflection S-parameter trace via inverse Fourier transformation. The
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.
User Manual 1173.9163.02 ─ 62
Concepts and features
Optional extensions and accessories
235