Simple model of 1/f noise

Simple analytically solvable model of 1/f noise is proposed. The model consists of one or few particles moving in the closed contour. The drift period of the particle round the contour fluctuates about some average value, e.g. due to the external random perturbations of the system's parameters. The model contains only one relaxation rate, however, the power spectral density of the current of particles reveals an exact 1/f spectrum in any desirable wide range of frequency and can be expressed by the Hooge formula. It is likely that the analysis and the generalizations of the model can strongly influence on the understanding of the origin of 1/f noise.