R&S FSH3 Setting and Using the Measurement Functions
Cable Measurements
(Only for R&S FSH3 with tracking generator (Order No. 1145.5850.13 or 1145.5850.23) and with option
R&S FSH-B1 (Distance-To-Fault Measurements) installed).
Measurements to determine the characteristics of cables to the antenna are key tasks when
transmission equipment is being installed or maintained. Cable damage or bad connections have an
adverse effect on the efficiency of the transmitter system. In conjunction with a tracking generator and
the option "Distance-To-Fault Measurement" (DTF, R&S FSH-B1), the R&S FSH3 can locate cable
faults and determine their distance from the measurement plane.
The only inputs required are the cable type and the approximate length. Using these parameters, the
R&S FSH3 measures the distance to any faults and the degree of mismatch. It is easy to define the
cable characteristics with the supplied "FSH View" software package and to transfer them to the
R&S FSH3. Up to 10 cable types can be stored by the R&S FSH3.
The R&S FSH3 measures the sum of the tracking generator signal and the signal reflected by the cable
under test in the frequency domain. Depending on the phase of the signal reflected at a fault relative to
the generator signal there is either reinforcement or cancellation. Because of this effect there is ripple
on the received sum signal in the frequency domain. The R&S FSH3 fast Fourier transforms the
received signal to the time domain. Using the characteristic data of the cable under test, the R&S FSH3
directly calculates how far the reflections have travelled from the fault. The magnitude of the fault is
given by the height of the reflection at a certain distance.
Test setup:
¾ Connect the cable of the VSWR Bridge R&S FSH-Z2 to the power sensor input on the R&S FSH3.
¾ Connect the bridge to the generator output and the RF input on the R&S FSH3.
¾ Connect the cable supplied with option R&S FSH-B1 to the bridge input.
Note: For distance-to-fault measurements, a cable of one meter length must be connected to the
output of the R&S FSH-Z2. Results are useless without this cable.
1145.5973.12 4.65 E-6
To Next Page
Loading...
