  Techniques of calculation of emission line profiles formed in a non--uniform
accretion disk is presented. Change of the profile shape as a function of phase
turn of the disk with a bright spot on the surface is analysed. A possibility
of a unambiguous determination of the disk and spot parameters is considered,
the accuracy of their determination is estimated. The results of calculations
show that the analysis of spectra obtained at different phases of the orbital
period gives a possibility of estimating the basic parameters of the spot (such
as geometric size and luminosity) and to investigate the structure of the
accretion disk.
