  Masses of pseudoscalar and vector mesons, which are ground states of light
or/and heavy quarks and antiquarks, have been calculated in the framework of an
extended model of quasi-independent quarks with absolute uncertainties about 30
MeV. It is shown that the assumption on equidistant discrete levels for a mean
field energy does not contradict to existing data and permits to reduce a
number of model parameters. It is obtained, that a difference between
neighbouring mean field energy levels is flavour independent. Values of
spin-spin interaction between quarks and antiquarks with different flavours in
pseudoscalar and vector mesons are presented.
