Patent ID: 7693034
Filing Date: 2010-04-06
Classification: G06F,H04L

Abstract:
1. A circuit for converting frequency domain information to time domain information comprising: a. an Inverse Fast Fourier Transform circuit having a length of N samples, the Inverse Fast Fourier Transform circuit adapted to receive input data of length N samples, to circularly shift the input data by m samples; and to generate output data of length N samples not multiplied by external rotator coefficients that are circularly shifted by m samples, where m is less than N; and b. a Cyclical Prefix Insertion circuit adapted to insert a cyclical prefix of length m, the Cyclical Prefix Insertion circuit having; wherein the N samples is a power of 2 and wherein the Inverse Fast Fourier Transform circuit implements an algorithm selected from the group consisting of Radix-2 and Radix-2 wherein the Inverse Fast Fourier Transform circuit further comprises a plurality of butterfly circuits, rotator circuits and multiplier circuits with memories, all coupled to a control circuit, and the Inverse Fast Fourier Transform is adapted to circularly shift the input data by m samples by modifying memory contents for at least one multiplier circuit with memory and modifying the control for at least one rotator circuit.