Efficient implementations of pipelined CORDIC based IIR digital filters using fast orthonormal μ-rotations

In this correspondence, an efficient implementation of pipelined coordinate rotation digital computer (CORDIC)-based IIR digital filters based on fast orthonormal μ-rotations is proposed. Using this method, the Givens rotations are approximated by angles corresponding to orthonormal μ rotations, which are based on the idea of CORDIC and can perform rotation with minimal number of shift-add operations. We present various methods of construction for such orthonormal μ rotations. A significant reduction (over 70%) of the number of required shift-add operations is achieved. All types of fast rotations can be implemented as a cascade of only four basic types of shift-add stages. These stages can be executed on a modified floating-point CORDIC architecture, making the pipelined filter highly suitable for VLSI implementations