Patent ID: 8275820
Filing Date: 2012-09-25
Classification: G01S,G06F,H04L

Abstract:
1. A variable length fast Fourier transform (FFT) system, comprising: a plurality of cascaded butterfly stages, each containing at least one of processing elements; at least one divide switch for dividing the connection of said processing elements or said cascaded butterfly stages according to a bypassing signal to perform either a first data length FFT operation, or a second data length FFT operation, wherein the second data length is shorter than the first data length; a mode switch for generating the bypassing signal and a control signal depended on requirements of different data lengths for different FFT operation modes; and at least one multiplexer which is selectively switched by different levels of the control signal from the mode switch to output either of two different kinds of twiddle factors to a corresponding multiplier interposing between the neighboring butterfly stages for generating a twiddle factor multiplication product.