Abstract: A measurement system for determining at least one characteristic of a device under test (DUT) at at least one frequency is described. The measurement system comprises a network analyzer being in connection at least with a first source via a first connector and a second source via a second connector. Each source generates a signal. The network analyzer further comprises signal paths arranged for applying the generated signals to the DUT and arranged for receiving signals output by the DUT. The frequency content of the signal generated by the second source comprises at least a frequency component offset from the at least one frequency at which the DUT is characterized, the at least one frequency being comprised in the frequency content of the signal generated by the first source.