Signal exploitation by time and frequency correlation
Douglas J. Nelson, Joshua A. Tempkin · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2001
We address two classical problems relating to harmonic signals. The first of these is the blind recovery of the carrier of a single sideband-AM communication signal, and the second is the isolation and blind estimation of the fundamental of a time-varying harmonic signal. The methods are based on cross-spectra estimated from the short time Fourier transform, a generalization of the Chinese remainder theorem and joint Fourier and autocorrelation representations of the signal spectrum. These tools are developed, and their utility is demonstrated in the solutions of the two problems. By an additional application of a frequency-lag autocorrelation function, it is demonstrated that the harmonic fundamental can be recovered, even if it is not present in the original spectrum.