Practical aspects of a fast algorithm for frequency detection

Previous works by the authors have advanced a novel frequency location technique based on recursive filtering concepts. The complexity is proportional to the signal length, which motivates the term, “fast.” Asymptotic theory reported elsewhere does not give the full picture. The main objective is to discuss practical computational considerations, and through simulation, compare the performance of our algorithm with alternatives. The gist of our findings is that for low signal-to-noise power ratios, our method is supreme among the available fast detectors. There is a theoretical reason to anticipate this. We have extended earlier explorations by devising an enhancement which simultaneously narrows the bandwidth while the location recursion proceeds. The effect is to vastly amplify the signal-to-noise ratio as the detector homes in on the target frequency. A practical procedure is offered which, experimentally, appears to be an effective guide in determining whether the detector output is meaningful or spurious (because the signal is too weak, or is nonexistent)