HP 54753A User Manual page 104

Measure and Other TDR Specific Menus
TDR/TDT Measure Menu
TDR Maximum Reflection
Pressing the TDR maximum reflection softkey display the automatically calculated
maximum percent reflection value at the bottom of the display under the
waveform graticule.
The TDR plug-in module must be calibrated and a reference plane established
before this measurement can be selected.
The calculated value is dependant on the type of response and stimulus that
are selected.
For differential response to differential stimulus and common mode response
to common mode stimulus, the following formula is used:
Maximum reflection =
where:
V = the maximum voltage value along the waveform
max
V = the channel 1 reference plane voltage into a 50 ohm load
1ref50Ω
V = the channel 1 reference plane voltage into a short
1ref0Ω
= the channel 2 reference plane voltage into a 50 ohm load
V
2ref50Ω
V = the channel 2 reference plane voltage into a short
2ref0Ω
For differential response to common mode stimulus and common mode
response to differential stimulus, the following formula is used.
Maximum reflection =
where:
= the maximum voltage value along the waveform
V
max
V = the channel 1 reference plane voltage into a 50 ohm load
1ref50Ω
V = the channel 1 reference plane voltage into a short
1ref0Ω
V = the channel 2 reference plane voltage into a 50 ohm load
2ref50Ω
V = the channel 2 reference plane voltage into a short
2ref0Ω
6-6
(
V – V
max 1ref50Ω
100 ------------------------------------------------------------------------------------------------------------ -
( )
V – V
1ref50Ω 1ref0Ω
(
V – V
1ref50Ω
max
----------------------------------------------------------------------- -
100 ------------------------------------------------------------------------------------------------------------ -
(
V – V
1ref50Ω 1ref0Ω
------------------------------------------------------------------------------------------------------------ -
)
+ V
2ref50Ω
( )
+ V – V
2ref50Ω 2ref0Ω
)
+ V
2ref50Ω
2
) ( )
+ V – V
2ref50Ω 2ref0Ω
2