ROM-BASED COMPLEX MULTIPLIER USEFUL FOR FFT BUTTERFLY ARITHMETIC UNIT

A four-port digital complex multiplier useful for FFT butterfly arithmetic units and in which ROM's are employed as square function look-up tables. Each of the four ports is responsive to a respective one of the component values of two complex numbers. The square-function look-up memories are responsive to various ones of the input ports and cooperate with quarter-square-multipliers to provide component complex products. An output subtractor and an output summer, responsive to mutually exclusive pairs of the quarter-square multipliers, provide a respective real and imaginary component of the product of the two complex numbers.