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Figure 3.6 Return Loss or VSWR Test Connection Diagram
7. You can adjust the the amplitude display for easy observation by methods implied in Section 3.5; then, press
【
Marker
】
to
turn on marker function, so that you can check the return loss conditions of the cable at each frequency.
Return loss or VSWR is the matching degree of DUT at each frequency point in the whole frequency band. Sweep span can be
specifically set according to operating frequency of the measured cable or DUT during measurement.
3.2.2.
Cable Loss Measurement
Cable Loss refers to the energy consumed by cable in the process of signal transmission, which is generally represented by average
value. During the test, the cable loss is usually measured by the following connection, as shown in Figure 3.7.
Figure 3.7 Cable Loss Measurement Connections
Now, this part takes the cable with length of 25m, frequency of 2.1GHz and cable loss of 0.36dB/m to introduce the cable loss test
steps.
1. Press
【
Meas
】
to enter measurement menu;
2. Select [Cable Loss] menu to set the current measurement format of instrument as “Cable Loss”.
3. Press
【
Freq
】
to enter the frequency menu; select [Start Freq] menu, then use the numeric keys, knob or arrow keys to input
the start frequency value and select the corresponding unit menu to complete the input; the frequency in this example is set to
1MHz.
4. Similar to step 3, set the stop frequency needed by the measurement; the frequency in this example is set to 4GHz.
5. According to the section 1 in chapter 3, calibrate at port 1 of the instrument;
Measured cable
