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  2. Nyquist frequency - Wikipedia

    en.wikipedia.org/wiki/Nyquist_frequency

    In this example, f s is the sampling rate, and 0.5 cycle/sample × f s is the corresponding Nyquist frequency. The black dot plotted at 0.6 f s represents the amplitude and frequency of a sinusoidal function whose frequency is 60% of the sample rate. The other three dots indicate the frequencies and amplitudes of three other sinusoids that ...

  3. Aliasing - Wikipedia

    en.wikipedia.org/wiki/Aliasing

    Fig.5: Graph of frequency aliasing, showing folding frequency and periodicity. Frequencies above f s /2 have an alias below f s /2, whose value is given by this graph. Two complex sinusoids, colored gold and cyan, that fit the same sets of real and imaginary sample points when sampled at the rate ( f s ) indicated by the grid lines.

  4. Range ambiguity resolution - Wikipedia

    en.wikipedia.org/wiki/Range_ambiguity_resolution

    Range aliasing occurs when reflections arrive from distances that exceed the distance between transmit pulses at a specific pulse repetition frequency (PRF). Range ambiguity resolution is required to obtain the true range when the measurements are made using a system where the following inequality is true.

  5. Nyquist–Shannon sampling theorem - Wikipedia

    en.wikipedia.org/wiki/Nyquist–Shannon_sampling...

    Effects of aliasing, blurring, and sharpening may be adjusted with digital filtering implemented in software, which necessarily follows the theoretical principles. A family of sinusoids at the critical frequency, all having the same sample sequences of alternating +1 and –1.

  6. Downsampling (signal processing) - Wikipedia

    en.wikipedia.org/wiki/Downsampling_(signal...

    Reduce high-frequency signal components with a digital lowpass filter. Decimate the filtered signal by M; that is, keep only every M th sample. Step 2 alone creates undesirable aliasing (i.e. high-frequency signal components will copy into the lower frequency band and be mistaken for lower frequencies). Step 1, when necessary, suppresses ...

  7. Spectral leakage - Wikipedia

    en.wikipedia.org/wiki/Spectral_leakage

    The frequency axis has units of FFT "bins" when the window of length N is applied to data and a transform of length N is computed. For instance, the value at frequency ⁠ 1 / 2 ⁠ "bin" is the response that would be measured in bins k and k + 1 to a sinusoidal signal at frequency k + ⁠ 1 / 2 ⁠. It is relative to the maximum possible ...

  8. Chirp spectrum - Wikipedia

    en.wikipedia.org/wiki/Chirp_spectrum

    In addition, a number of mathematical software programs, such as Mathcad, MATLAB and Mathematica have built-in routines to evaluate the integrals, either as standard functions or in extension packages. Some plots of the power spectrum |S(ω)| 2 as a function of frequency are shown, for time-bandwidth products of 25, 100, 250 and 1000. When the ...

  9. Stroboscopic effect - Wikipedia

    en.wikipedia.org/wiki/Stroboscopic_effect

    The magnitude, shape, periodicity and frequency of the TLMs will depend on many factors such as the type of light source, the electrical mains-supply frequency, the driver or ballast technology and type of light regulation technology applied (e.g. pulse-width modulation).