Spectral Window Weightings

Controlling the Trade Space
  • James K. Beard
Chapter

Abstract

A spectral widow weight is a function applied to the time domain data that changes the frequency domain representation in a controllable way. Nearly always, a spectral window function is a symmetrical bell-shaped curve that de-emphasizes the ends of the intervals of the time data. Its effect is observed by the DFT response to a sine wave of variable frequency and phase. Without a window weight function, the output of an FFT follows the familiar sine of x over x shape except when the frequency of the tone is exactly positioned at the center of a frequency bin. In a plot of amplitude in decibels versus frequency, this is the familiar Christmas-tree shape. With a spectral window, the main lobe is broadened slightly, while the sidelobes are lowered, particularly the near-in sidelobes.

Keywords

Frequency Response Main Lobe Beam Pattern Finite Impulse Response Filter Spectral Window 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media New York 2004

Authors and Affiliations

  • James K. Beard
    • 1
  1. 1.Systems and SensorsLockheed Martin MarineUSA

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