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  2. Time–frequency representation - Wikipedia

    en.wikipedia.org/wiki/Time–frequency...

    A signal, as a function of time, may be considered as a representation with perfect time resolution.In contrast, the magnitude of the Fourier transform (FT) of the signal may be considered as a representation with perfect spectral resolution but with no time information because the magnitude of the FT conveys frequency content but it fails to convey when, in time, different events occur in the ...

  3. Time-scale calculus - Wikipedia

    en.wikipedia.org/wiki/Time-scale_calculus

    The three most popular examples of calculus on time scales are differential calculus, difference calculus, and quantum calculus. Dynamic equations on a time scale have a potential for applications such as in population dynamics. For example, they can model insect populations that evolve continuously while in season, die out in winter while ...

  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. Time domain - Wikipedia

    en.wikipedia.org/wiki/Time_domain

    Time domain refers to the analysis of mathematical functions, physical signals or time series of economic or environmental data, with respect to time. In the time domain, the signal or function's value is known for all real numbers, for the case of continuous time, or at various separate instants in the case of discrete time.

  6. Time series - Wikipedia

    en.wikipedia.org/wiki/Time_series

    One can distinguish two major classes of function approximation problems: First, for known target functions, approximation theory is the branch of numerical analysis that investigates how certain known functions (for example, special functions) can be approximated by a specific class of functions (for example, polynomials or rational functions ...

  7. Mean time between failures - Wikipedia

    en.wikipedia.org/wiki/Mean_time_between_failures

    Mean time between failures (MTBF) describes the expected time between two failures for a repairable system. For example, three identical systems starting to function properly at time 0 are working until all of them fail. The first system fails after 100 hours, the second after 120 hours and the third after 130 hours.

  8. Basis expansion time-frequency analysis - Wikipedia

    en.wikipedia.org/wiki/Basis_Expansion_Time...

    2 Examples. Toggle Examples subsection. 2.1 Three-parameter atoms. ... Jian-Jiun Ding, Time frequency analysis and wavelet transform class note, Department of ...

  9. Longitudinal study - Wikipedia

    en.wikipedia.org/wiki/Longitudinal_study

    The sample comprises people born on one of four selected dates of birth and therefore makes up about 1% of the total population. The sample was initiated at the time of the 1971 Census, and the four dates were used to update the sample at the 1981,1991, 2001 and 2011 Censuses and in routine event registrations.