HP 54753A - Page 162

Differential TDR Measurements
Measuring Differential and Common Mode Impedance
8-14
Measuring Common Mode Impedance
We are now ready to measure the common mode impedance of the differential
line. This section assumes that the differential mode impedance section has
been completed and that the oscilloscope settings have not been changed.
1
Press the
TDR/TDT Setup key.
2
Press the
Stimulus softkey and select common mode.
3
Press the
Enter
softkey.
4
Press the
TDR response 1 differential . . .
softkey.
5
Press the
Response softkey and select common mode.
6
Press the
Enter softkey.
7
Press the
Done
softkey (Figure 8-9).
Figure 8-9
The common mode impedance of two 50 ohm uncoupled lines is 25 ohms.