METHOD AND DEVICE FOR COMPUTING MATRICES FOR DISCRETE FOURIER TRANSFORM (DFT) COEFFICIENTS

摘要

A method of computing matrices of discrete-frequency Discrete Fourier Transform (DFT) coefficients, the method including the steps of (a) for a first frame (10) of samples, multiplying a frame of samples of a discrete-time signal by a twiddle factor matrix (F1, F2) to compute a matrix of DFT coefficients for that first frame, and storing a computation resulting from multiplication of the second half of the frame (b) of samples by the right half (F2) of the twiddle factor matrix; and (b) for each subsequent frame (12, 14) of samples, wherein each subsequent frame overlaps a preceding frame by half, (i) retrieving the stored computation from the preceding frame, inverting the sign of the stored computation every second frame; (ii) multiplying the second half of the current frame of samples by the right half of the twiddle factor matrix, and storing the resultant computation; and (iii) adding the results of steps (i) and (ii).