Improved IIR adaptive line enhancement for tracking sinusoids in noise

The classical problem of extracting an unknown sinusoid from a noise background has many partial solutions but no definitive ones. Several different adaptive filter algorithms can be made to acquire and track the sinusoidal signal and so improve the signal-to-noise ratio. One particular type of filter is the adaptive line enhancer (ALE), which is at its most efficient when executed with an IIR adaptive section. The principle of the basic structure of the ALE is explained and experimental procedures discussed. The adjustment of pole frequency and radius are described, with consideration of the normalised least mean squares (NLMS) algorithm