Disclosed is an arrangement for quickly measuring the phase distribution or the component distribution in a flow cross section for substance mixtures also of a non-conducting type by measuring the complex electrical admittance. Said arrangement essentially features the following: at least one sine wave generator (5) which is mounted upstream from the transmitter electrodes (3a) of the excitation level and applies an alternating voltage to the transmitter electrodes (3a); current-to-voltage converters (7) which are mounted downstream from the receiver electrodes (3b), amplify the alternating current that flows from at least one excitation electrode (3a) through the medium to the receiver electrodes (3b), and convert said alternating current into a voltage signal; filter groups (10, 11, 16) and vector voltmeters (8) which are mounted downstream from the current-to-voltage converters (7) and allow the complex signal ratio Ua/Ue to be metrologically detected.