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  2. Cutoff frequency - Wikipedia

    en.wikipedia.org/wiki/Cutoff_frequency

    The cutoff frequency is the critical frequency between propagation and attenuation, which corresponds to the frequency at which the longitudinal wavenumber is zero. It is given by ω c = c ( n π a ) 2 + ( m π b ) 2 {\displaystyle \omega _{c}=c{\sqrt {\left({\frac {n\pi }{a}}\right)^{2}+\left({\frac {m\pi }{b}}\right)^{2}}}} The wave equations ...

  3. Fourier shell correlation - Wikipedia

    en.wikipedia.org/wiki/Fourier_shell_correlation

    In structural biology, as well as in virtually all sciences that produce three-dimensional data, the Fourier shell correlation (FSC) measures the normalised cross-correlation coefficient between two 3-dimensional volumes over corresponding shells in Fourier space (i.e., as a function of spatial frequency [1]).

  4. Spatial cutoff frequency - Wikipedia

    en.wikipedia.org/wiki/Spatial_cutoff_frequency

    As an example, a telescope having an f /6 objective and imaging at 0.55 micrometers has a spatial cutoff frequency of 303 cycles/millimeter. High-resolution black-and-white film is capable of resolving details on the film as small as 3 micrometers or smaller, thus its cutoff frequency is about 150 cycles/millimeter.

  5. Genotype frequency - Wikipedia

    en.wikipedia.org/wiki/Genotype_frequency

    if the allele A frequency is denoted by the symbol p and the allele a frequency denoted by q, then p+q=1. For example, if p=0.7, then q must be 0.3. In other words, if the allele frequency of A equals 70%, the remaining 30% of the alleles must be a, because together they equal 100%. [5]

  6. Optical transfer function - Wikipedia

    en.wikipedia.org/wiki/Optical_transfer_function

    The 50% cutoff frequency is determined to yield the corresponding spatial frequency. Thus, the approximate position of best focus of the unit under test is determined from this data. The MTF data versus spatial frequency is normalized by fitting a sixth order polynomial to it, making a smooth curve.

  7. Roll-off - Wikipedia

    en.wikipedia.org/wiki/Roll-off

    For some filter classes, such as the Butterworth filter, the insertion loss is still monotonically increasing with frequency and quickly asymptotically converges to a roll-off of 20n dB/decade, but in others, such as the Chebyshev or elliptic filter the roll-off near the cut-off frequency is much faster and elsewhere the response is anything ...

  8. Waveguide - Wikipedia

    en.wikipedia.org/wiki/Waveguide

    The mode with the lowest cutoff frequency is the fundamental mode of the waveguide, and its cutoff frequency is the waveguide cutoff frequency. [ 15 ] : 38 Propagation modes are computed by solving the Helmholtz equation alongside a set of boundary conditions depending on the geometrical shape and materials bounding the region.

  9. Cutoff - Wikipedia

    en.wikipedia.org/wiki/Cutoff

    Cutoff (reference value), a one-sided reference range in health-related fields. Cutoff (steam engine), the point in the piston stroke at which the inlet valve is closed. Cutoff frequency, in telecommunications and digital signal processing. Cutoff grade, in mining, the level of mineral in an ore below which it is not economically feasible to ...