DSP (CHARACTERISTICS OF WINDOW)

 CHARACTERISTICS OF WINDOW:

  • MAIN LOBE WIDTH: The measure of the main lobe width at -3dB or -6dB below the main lobe peak. When the main lobe width decreases, the remaining energy spreads out to the side lobes and thereby decreasing the detection ability. A compromise is needed to find the balance between detection and resolution fitting for a given application.
  • SIDE LOBES : Side lobes occur at either side of the main lobe. They approach zero at integral multiples of Fs/N where Fs=sampling frequency and N is the length of N-point FFT/DFT. Side lobes directly affect the extent to which the adjacent frequency components leak into the adjacent frequency bins.
  • SIDE LOBE HEIGHT : The side lobe height is usually measured for the side lobe with the maximum peak compared to other side lobes. It is measured in decibels relative to the peak of the main lobe.
  • SIDE LOBE ROLL-OFF RATE : The asymptotic decay rate in decibels per decade of the frequency of the side lobes’ peaks.
  • EQUIVALENT NOISE BANDWIDTH : The equivalent width of a rectangular filter that passes the same amount of white noise as the window.


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