How does a vector network analyzer obtain phase information?

[DSPly]

Hi

I am wondering in which way a vector network analyzer obtains the phase information (in SFCW / FMCW mode).

Can someone provide me further information about how an VNA works?

Thanks!

 

[f95toli]

AFAIK they just use what is in essence an IQ demodulator, i.e. the phase is calculated from the I(nphase) and Q(uadrature) components of the signal.

Measuring phase is actually quite easy (all you need is a saturated mixer), doing it accurately is a bit more tricky.