Phase- and group delay measurements over large distances

The paper presents a new technique to measure group delay and relative phase by using a two tone signal. It is ideal for measuring group delay and relative phase at frequency converting components without LO access and also works if the LO frequency is unstable. This method is extended to perform measurements on test ports separated by a large distance. The only requirement is two vector network analyzers, one at each test port, but no coaxial connection between both instruments. The communication between both instruments is established via a LAN/LXI interface.