Extending coherence for optimal detection of nonstationary harmonic signals

This paper describes an improved detector for nonstationary harmonic signals. The performance improvement is accomplished by using a novel method for extending the coherence time of such signals. This method applies a transformation to a noisy signal that attempts to fit a simple model to the signal´s slowly changing fundamental frequency over the analysis duration. By matching the change in the signal´s fundamental frequency, analysis is more coherent with the signal over longer durations, which allows the use of longer windows and thus improves detection performance.