Patent ID: 6434583
Filing Date: 2002-08-13
Classification: G06F,H03M,H04B,H04H,H04J,H04K,H04L,H04M,H04N,H04W,Y02D

Abstract:
An apparatus for providing a Fast Fourier Transform to convert a signal between time and frequency domains comprising:a radix-N core, the radix-N core including: at least N multipliers; a twiddle-factor lookup table storing complex twiddle factors, the twiddle-factor lookup table coupled to one input of each one of the multipliers; a conversion random access memory storing transform points, the conversion random access memory coupled to another input of each one of the multipliers; an array of at least N-times-N adder-subtractor-accumulators; a set of holding latches that hold both a real and imaginary portion respectively of a first transform point, and wherein a fetch of a real portion of a first twiddle factor from the twiddle-factor lookup table is interleaved in time with a fetch of an imaginary portion of the first twiddle factor, and two substantially simultaneous first and second multiply operations take place in the N multipliers to multiply the real portion of first twiddle factor by the real and imaginary portion respectively of the first transform point, and two substantially simultaneous third and fourth multiply operations take place in the N multipliers to multiply the imaginary portion of the first twiddle factor by the real and imaginary portion respectively of the first transform point.