HP 54753A User Manual page 193

Shunt resistance,
for Z
Shunt resistance,
The incident step and the reflections will be attenuated considerably. Refer to
Figure 9-17. The sacrifice made to achieve the reflectionless connection is
sensitivity, and a loss of calibration. It is a good rule of thumb to use the L-pad
technique when major discontinuities are to be encountered and a tapered
section when small discontinuities are present (such as in cable testing).
The ±100% reflection points may be determined with the voltage markers and
by using a short and open at the transmission line's end.
Figure 9-17
Α 50 Ω TDR System with a Matching L-Pad to the 75
= ±1 is Reduced Using the Matching L-Pad
R =
2
< 50 Ω:
o
Resistance in series with source,
R =
2
50Z
o
----------- -
R
1
(
R = 50 50 Z
2
50Z
o
----------- -
R
1
Ω
cable. The Amplitude Corresponding to Rho
TDR Fundamentals
Step Reflection Testing
)
–
o
9-19