What is the smallest discontinuity that can be measured with a TDR oscilloscope?

What is the smallest discontinuity that can be measured with a TDR oscilloscope?

Two discontinuities will be observed as two separate ones if the distance between them is at least half the TDR rise time. There is no similar rule for how small a single discontinuity can be, but such discontinuity cannot be much smaller that half the TDR rise time until it can no longer be resolved. Nonetheless, smaller discontinuities can be analyzed and electrically characterized, but you will need to do relative or comparative TDR measurements, as described in our application notes on electrical characterization of packages, connectors and sockets, and on package failure analysis. Download our application notes to learn more.