An unbiased adaptive method for retrieval of sinusoidal signals in colored noise

The problem of retrieving narrowband or sinusoidal signals in additive noise, colored or white, is considered in this paper. A frequency-domain analysis leads to a notch filter estimator producing unbiased estimates of the sinusoidal frequencies. The notch filter lends itself naturally to a frequency decoupled realization i.e. cascaded form realization. This has desirable numerical consequences which is essential for resolving closely spaced spectral lines. The method also features an adjustable debiasing parameter ?? whose proper adjustment results in a decent rate of convergence to highly accurate estimates. Based on some frequency-tracking simulations, the method also appears to possess good tracking capability.