  General relativity can be formulated either as in its original geometrical
version (Einstein, 1915) or as a field theory (Feynman, 1962). In the Feynman
presentation of Einstein theory an hypothesis concerning the interaction of
gravity to gravity, which was hidden in the original version, becomes explicit.
This is nothing but the assumed extension of the validity of the equivalence
principle not only for matter-gravity interaction, but also for
gravity-gravity. Recently we have presented a field theory of gravity (from
here on called the NDL theory) which does not contain such a hypothesis. We
have shown that, for this theory, both the cosmological structure and the PPN
approximation for the solar tests are satisfied.
  The proposal of this paper is to go one step further and to show that NDL
theory is able to solve the problem of radiation emission by a binary pulsar in
the same degree of accuracy as it was done in the GR theory. In the
post-Newtonian order of approximation we show that the quadrupole formula of
this theory is equal to the corresponding one in general relativity. Thus, the
unique actual observable distinction of these theories concerns the velocity of
gravitational waves, which becomes then the true ultimate test for gravity
theory.
