Hello , I was told that calibration sets the TDR t=0 point in the cable.
why is that?
Thanks.

 

?? https://www.google.com/search?channel=entpr&q=TDR+t=0+point+in+the+cable

 

Hello , I was told that calibration sets the TDR t=0 point in the cable.
why is that?
Thanks.

It doesn’t.

Instead VNA calibration shifts the calibration point to the end of the cabling where the DUT is to be connected.
Calibration removes cabling and connectors from influencing the measurement.

 

Basically the same as a spectrum analyzer with a tracking generator,


Normalized frequency response of a jumper wire.


Remove the jumper wire. A quick and dirty Interdigital Filter response plot using that normalized wire calibration.

 

Basically the same as a spectrum analyzer with a tracking generator,

View attachment 369052
Normalized frequency response of a jumper wire.

View attachment 369053
Remove the jumper wire. A quick and dirty Interdigital Filter response plot using that normalized wire calibration.

Well sorta but not quite.
Where a VNA has bidirectional ports a spectrum analyzer doesn’t so must use an external reflection bridge for the likes of S11 measurements whereas a S21 measurement is a through measurement using the stimulus of the Tracking generator.

 

Well sorta but not quite.
Where a VNA has bidirectional ports a spectrum analyzer doesn’t so must use an external reflection bridge for the likes of S11 measurements whereas a S21 measurement is a through measurement using the stimulus of the Tracking generator.

Sure, it's just a visual to show what can be 'normalized".

https://forum.allaboutcircuits.com/threads/type-of-electrical-circuit.178907/post-1628195