Adaptive Windowing of FFT Data for Increased Resolution and Sidelobe Rejection
Fast Fourier Transforms (FFTs) are used for processing observed signals. Weighing functions, referred to as windows, are applied to the data to reduce the spectral leakage associated with finite observation intervals. Thus, in applying windows to a sample data harmonic analysis, undesirable effects due to spectral leakage are attempted to be removed. An indicator of how well a window suppresses leakage is the peak sidelobe level. Another indicator is the asymptotic rate of fall off of the sidelobes. However, an undesirable property associated with windowing is that the main lobe is widened. This results in a loss of spectral resolution.
It is an object of the present invention to provide a new class of windows that are not shift-invariant.
It is another object of the present invention to provide shift-variant windows that are data dependent and exhibit excellent sidelobe rejection and spectral resolution on simple spectra.
It is a further object of the present invention to provide better resolution and signal-to-noise resolution than other known windowing techniques.
These objectives, together with other objectives and advantages which will be subsequently apparent, reside in the details of the method and operation as more fully described and claimed hereinafter, reference being had to the accompanying drawings forming a part hereof, wherein like reference numerals refer to like parts throughout.
Patent Status: U.S. patent(s) 6,298,363 issued.CONTACT: