Alternatives for low-complexity complex rotators

Complex rotations find use in common transforms such as the Discrete Cosine Transform (DCT) and the Discrete Fourier Transform (DFT). In this work we consider low-complexity realization of constant angle rotators based on shifts, adders, and subtracters. The results show that redundant CORDIC and scaled constant multiplication are providing the best results, depending on which angle is considered. It is also shown that the precision can vary several bits using the same number of adders and subtracters, and, hence, the correct choice of rotator architecture is crucial for a low-complexity realization.