hannings

Hannings is not a standard technical term in itself. In common usage, it is often a misspelling or informal variant related to the Hann (or Hanning) window, a well-known function in digital signal processing.

The Hann window, named after Julius von Hann, is a raised-cosine window used to reduce spectral leakage in Fourier analysis. A typical form for a window of length N is w(n) = 0.5 [1 - cos(2πn/(N-1))], for n = 0, 1, ..., N-1. The Hanning window is an alternative spelling found in some texts, but it refers to the same function. This window provides a good balance between main-lobe width and sidelobe levels, making it a popular choice for spectrum estimation and filter design.

Properties and use include smooth transitions at the endpoints, moderate main-lobe width, and relatively low sidelobe levels compared with a rectangular window. It is often preferred in applications where leakage must be controlled without excessive loss of resolution. It is one of several window functions used in conjunction with the discrete Fourier transform to improve frequency-domain representations.

Etymology and nomenclature can cause confusion: Hann and Hanning refer to the same fundamental window, but “hannings” is not a standard term in formal documentation. When precision is required, it is advisable to use Hann window or Hanning window and to specify the exact formula and application context.

See also: window function, Hamming window, Blackman window, spectral leakage.