A vector network analyzer comprises a first measuring port, a first digital interface, connected to the first measuring port, adapted to be connected to a digital input or output of a device under test, and a second measuring port, adapted to be connected to a radio frequency input or output of the device under test. It also comprises a processor, adapted to determine S-parameters of the device under test based upon measuring signals transmitted to the device under test and receive from the device under test by the first measuring port and the second measuring port.