The problem on the Chandler period is an unsolved one. Several authors
suggested a hypothesis that the Chandler wobble is only one free peri
od which slightly changes in time and is amplitude-dependent. In this
paper, Ive shall examine the hypothesis more rigorous than that which
has been carried yet. A new deconvolution method for Fourier transform
is suggested. Using this method, the polar motion data since 1900 are
analysed and the varying process of the Chandlerian period and amplit
ude are given. The analytical results show that the Chandler period is
not stable and is indeed amplitude-dependent. The probable explanatio
n for this phenomenon is that it might be caused by non-equilibrium re
sponse of the ocean.