Method as well as test system for testing a device under test

A test system for testing a device under test, said test system comprising:

• at least one vector signal generator configured to generate a wideband modulated signal;
• at least one vector signal analyzer having a defined phase relation with said vector signal generator;
• and
• at least one directional element configured to separate incident electromagnetic waves and reflected electromagnetic waves,
• wherein said directional element has at least a first port, a second port and a third port, said vector signal generator being connected with said directional element via said first port, said vector signal analyzer being connected with said directional element via said second port, and said third port being provided for connecting a device under test,
• wherein said vector signal generator is configured to forward said wideband modulated signal to said device under test via said directional element,
• wherein said directional element is configured to separate an electromagnetic wave reflected at an input of said device under test,
• wherein said vector signal analyzer is configured to process a reference signal that is associated with said wideband modulated signal, and
• wherein said vector signal analyzer is configured to determine a channel response by taking said reference signal and at least one scattering parameter of said device under test into account, which is determined by said vector signal analyzer, wherein said scattering parameter depends on said reflected electromagnetic wave.