Patent US 4,354,249

The processing unit includes at least one complex multiplier having hour multiplying circuits for multiplying the real and imaginary components of two complex vectors and combining the products to produce a complex output vector. Representing the input complex vectors by (A+jB) and (C+jD) the output complex vector becomes (AC-BD)+j(BC+AD). The combining circuits can be switched so that one of the input complex vectors is conjugated and the output complex vector becomes (AC+BD)+j(BC-AD). Thus, the present processing unit can provide the dot product of two complex vectors or the like.