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  2. Frequency analysis - Wikipedia

    en.wikipedia.org/wiki/Frequency_analysis

    Frequency analysis is based on the fact that, in any given stretch of written language, certain letters and combinations of letters occur with varying frequencies. Moreover, there is a characteristic distribution of letters that is roughly the same for almost all samples of that language.

  3. Letter frequency - Wikipedia

    en.wikipedia.org/wiki/Letter_frequency

    Letter frequency is the number of times letters of the alphabet appear on average in written language.Letter frequency analysis dates back to the Arab mathematician Al-Kindi (c. AD 801–873), who formally developed the method to break ciphers.

  4. Time–frequency analysis - Wikipedia

    en.wikipedia.org/wiki/Time–frequency_analysis

    In signal processing, time–frequency analysis comprises those techniques that study a signal in both the time and frequency domains simultaneously, using various time–frequency representations. Rather than viewing a 1-dimensional signal (a function, real or complex-valued, whose domain is the real line) and some transform (another function ...

  5. Cumulative frequency analysis - Wikipedia

    en.wikipedia.org/wiki/Cumulative_frequency_analysis

    Cumulative frequency distribution, adapted cumulative probability distribution, and confidence intervals. Cumulative frequency analysis is the analysis of the frequency of occurrence of values of a phenomenon less than a reference value. The phenomenon may be time- or space-dependent. Cumulative frequency is also called frequency of non-exceedance.

  6. Frequency domain - Wikipedia

    en.wikipedia.org/wiki/Frequency_domain

    One of the main reasons for using a frequency-domain representation of a problem is to simplify the mathematical analysis. For mathematical systems governed by linear differential equations, a very important class of systems with many real-world applications, converting the description of the system from the time domain to a frequency domain converts the differential equations to algebraic ...

  7. Frequency (statistics) - Wikipedia

    en.wikipedia.org/wiki/Frequency_(statistics)

    In statistics, the frequency or absolute frequency of an event is the number of times the observation has occurred/been recorded in an experiment or study. [ 1 ] : 12–19 These frequencies are often depicted graphically or tabular form.

  8. Cepstrum - Wikipedia

    en.wikipedia.org/wiki/Cepstrum

    The method is a tool for investigating periodic structures in frequency spectra. The power cepstrum has applications in the analysis of human speech. The term cepstrum was derived by reversing the first four letters of spectrum. Operations on cepstra are labelled quefrency analysis (or quefrency alanysis [1]), liftering, or cepstral analysis.

  9. Frequency - Wikipedia

    en.wikipedia.org/wiki/Frequency

    Frequency (symbol f), most often measured in hertz (symbol: Hz), is the number of occurrences of a repeating event per unit of time. [1] It is also occasionally referred to as temporal frequency for clarity and to distinguish it from spatial frequency.