  In many practical problems it is not necessary to compute the DFT in a
perfect manner including some radar problems. In this article a new
multiplication free algorithm for approximate computation of the DFT is
introduced. All multiplications $(a\times b)$ in DFT are replaced by an
operator which computes $sign(a\times b)(|a|+|b|)$. The new transform is
especially useful when the signal processing algorithm requires correlations.
Ambiguity function in radar signal processing requires high number of
multiplications to compute the correlations. This new additive operator is used
to decrease the number of multiplications. Simulation examples involving
passive radars are presented.
