Relationship between UCHT and FFT

This paper presents relationships among unified complex Hadamard transform (UCHT) whose transformation matrix contains elements /spl plusmn/1 and /spl plusmn/i, Walsh-Hadamard transform (WHT) whose transformation matrix contains elements /spl plusmn/1, and Fast Fourier Transform (FFT). They are all related to each other by a key matrix, and FFT can be computed by using UCHT WHT and some twiddle factor matrices.