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  2. Time–frequency representation - Wikipedia

    en.wikipedia.org/wiki/Timefrequency...

    A time–frequency representation (TFR) is a view of a signal (taken to be a function of time) represented over both time and frequency. [1] Time–frequency analysis means analysis into the time–frequency domain provided by a TFR. This is achieved by using a formulation often called "Time–Frequency Distribution", abbreviated as TFD.

  3. Frequency domain - Wikipedia

    en.wikipedia.org/wiki/Frequency_domain

    A frequency-domain representation may describe either a static function or a particular time period of a dynamic function (signal or system). The frequency transform of a dynamic function is performed over a finite time period of that function and assumes the function repeats infinitely outside of that time period.

  4. Time–frequency analysis - Wikipedia

    en.wikipedia.org/wiki/Timefrequency_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. Fourier transform - Wikipedia

    en.wikipedia.org/wiki/Fourier_transform

    Eq.2 is a representation of () ... the Fourier transform is rotation by 90° in the time–frequency domain, and preserves the symplectic form. ...

  6. Time domain - Wikipedia

    en.wikipedia.org/wiki/Time_domain

    The component frequencies, spread across the frequency spectrum, are represented as peaks in the frequency 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 ...

  7. Gabor transform - Wikipedia

    en.wikipedia.org/wiki/Gabor_transform

    The Gabor transform, named after Dennis Gabor, is a special case of the short-time Fourier transform. It is used to determine the sinusoidal frequency and phase content of local sections of a signal as it changes over time. The function to be transformed is first multiplied by a Gaussian function, which can be regarded as a window function, and ...

  8. Fourier series - Wikipedia

    en.wikipedia.org/wiki/Fourier_series

    In engineering, particularly when the variable represents time, the coefficient sequence is called a frequency domain representation. Square brackets are often used to emphasize that the domain of this function is a discrete set of frequencies.

  9. Discrete-time Fourier transform - Wikipedia

    en.wikipedia.org/wiki/Discrete-time_Fourier...

    In mathematics, the discrete-time Fourier transform (DTFT) is a form of Fourier analysis that is applicable to a sequence of discrete values. The DTFT is often used to analyze samples of a continuous function. The term discrete-time refers to the fact that the transform operates on discrete data, often samples whose interval has units of time.