A new method of frequency response analysis of an adsorber, with modulation of the adsorbate molar supply instead of traditional modulation of the reservoir volume, is presented. A continuous mode of operation is considered, for three different types of mass transfer mechanisms inside the particle : Langmuir kinetics, micro-pore diffusion and parallel pore and surface diffusion. Frequency response to sinusoidal and square wave modes of perturbation are investigated. In the case of square-wave forcing function, the system pressure response contains higher harmonics, which makes the study of fast dynamics more feasible by using relatively low frequencies of the input perturbations and analyzing the higher harmonics in the output signal. Simulation results show that the in-phase characteristic function of the continuous-flow adsorber is the same as that of a batch or a semi-batch one, while the out-of-phase characteristic function differs substantially, showing a minimum and a maximum, or no extrema at all, depending on the overflow. The conditions for extrema existence are discussed. Parameter estimation from simulated FR with inlet flow-rate modulation is also presented.