Abstract: The present invention is related to a system (1) for determining a representation of a multi-tone signal (2) comprising a plurality of phase coherent tones, at least two of said phase coherent tones being modulated by a modulating signal, said system comprising an input (3) for applying the multi-tone signal (2), phase coherent mixing means (5) for demodulation in connection with data acquisition means (6) for digitization, said mixing means and data acquisition means arranged for being fed with the multi-tone signal and with a reference signal (8) comprising said phase coherent tones, each pair of phase coherent tones having a fixed phase difference, whereby the data acquisition means is arranged for being triggered by a trigger signal (4) for yielding a representation of said modulation signals with fixed delay, processing means (7) arranged for receiving digital signals output from the data acquisition means and for comparing phase information of a downconverted tone of the multi-tone signal after demodula

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 includes 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 includes 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 includes at least a frequency component offset from the at least one frequency at which the DUT is characterized, the at least one frequency being included in the frequency content of the signal generated by the first source.