The present invention is a novel method of performing spectral analysis on a digital signal. The received signal is segmented into a number of data blocks, which may be disjoint or overlapping. For each data block, the signal is differentiated, and the Gram-Schmidt process is used to obtain orthogonality between a signal and its derivative. The complex extension leads to computation of phase using either the inverse tangent function or the complex logarithm. Finally, frequency estimation follows through differentiation of the unwrapped phase.