New algorithm for design of low complexity twiddle factor multipliers in radix-2 FFT

In this paper, a new design algorithm is proposed to synthesize low complexity twiddle factor multipliers in radix-2 FFT. A prudently defined cost function has been proposed as a measure of hardware complexity when generating trigonometric expressions for the complex multiplier coefficients. The selected trigonometric expressions of the coefficients lead to cost efficient implementation of twiddle factor multipliers by maximizing the sharing of both trigonometric expressions and weight-two common subexpressions in the coefficients. The effectiveness of the proposed design algorithm are demonstrated using two design examples where the proposed solution saves up to 31% of arithmetic operator and multiplexer costs over other existing methods.