  A family of orthonormal bases, the ultrametric wavelet bases, is introduced
in quadratically integrable complex valued functions spaces for a wide family
of ultrametric spaces.
  A general family of pseudodifferential operators, acting on complex valued
functions on these ultrametric spaces is introduced. We show that these
operators are diagonal in the introduced ultrametric wavelet bases, and compute
the corresponding eigenvalues.
  We introduce the ultrametric change of variable, which maps the ultrametric
spaces under consideration onto positive half-line, and use this map to
construct non-homogeneous generalizations of wavelet bases.
