time domain reflectometry in PCB S-maram design for signal integrity

[yefj]

Hello , We design PCB , its basicly transmission lines of two ends.
we extract S-parameters,then we ussualy connect some PULSE source to test the signal integrity using (time domain reflectometry).

time domain reflectometry is being used for to get the impedance at every point of the path in which the pulse is traveled in, i dont see what it will give us.
What is the purpose of TDR in PCB design?
Thanks.

 

[FvM]

TDR is used with PCB test structures in impedance controlled manufacturing.

 

[yefj]

Hello FVM, could you please say what kid of faults we can find i PCB using impedance diagnostics of TDR?
i know only open circuit or shirt circuit faults)

 

[FvM]

It's not used to detect faults, that would be possible but is easier achieved with continuity tests. It's used to measure transmission lines with defined impedance and adjust manufacturing parameters if necessary.