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FFT Spectrum (Real-Imaginary » Single-shot) (G Dataflow)

Version:
    Last Modified: March 30, 2017

    Computes the FFT spectrum of a time-domain signal and returns the FFT results as real and imaginary parts.

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    window parameter

    A value that affects the output coefficients when window type is Kaiser, Gaussian, or Dolph-Chebyshev.

    If window type is any other type of window, this node ignores this input.

    This input represents the following information for each type of window:

    • Kaiser—Beta parameter
    • Gaussian—Standard deviation
    • Dolph-Chebyshev—The ratio, s, of the main lobe to the side lobe

    Default: NaN—Causes this node to set beta to 0 for a Kaiser window, the standard deviation to 0.2 for a Gaussian window, and s to 60 for a Dolph-Chebyshev window

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    window type

    Time-domain window to apply to the signal.

    Name Value Description
    Rectangle 0 Applies a rectangle window.
    Hanning 1 Applies a Hanning window.
    Hamming 2 Applies a Hamming window.
    Blackman-Harris 3 Applies a Blackman-Harris window.
    Exact Blackman 4 Applies an Exact Blackman window.
    Blackman 5 Applies a Blackman window.
    Flat Top 6 Applies a Flat Top window.
    4 Term B-Harris 7 Applies a 4 Term B-Harris window.
    7 Term B-Harris 8 Applies a 7 Term B-Harris window.
    Low Sidelobe 9 Applies a Low Sidelobe window.
    Blackman Nutall 11 Applies a Blackman Nutall window.
    Triangle 30 Applies a Triangle window.
    Bartlett-Hanning 31 Applies a Bartlett-Hanning window.
    Bohman 32 Applies a Bohman window.
    Parzen 33 Applies a Parzen window.
    Welch 34 Applies a Welch window.
    Kaiser 60 Applies a Kaiser window.
    Dolph-Chebyshev 61 Applies a Dolph-Chebyshev window.
    Gaussian 62 Applies a Gaussian window.
    Force 64 Applies a Force window.
    Exponential 65 Applies an Exponential window.

    Default: Rectangle

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    signal

    Input signal.

    This input accepts the following data types:

    • Waveform
    • Waveform in complex double-precision, floating-point numbers
    • 1D array of waveforms
    • 1D array of waveforms in complex double-precision, floating-point numbers
    • 1D array of double-precision, floating-point numbers
    • 1D array of complex double-precision, floating-point numbers
    • 2D array of double-precision, floating-point numbers
    • 2D array of complex double-precision, floating-point numbers
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    error in

    Error conditions that occur before this node runs.

    The node responds to this input according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Default: No error

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    dt

    Sample period of the time-domain signal in seconds.

    Set this input to 1/fs, where fs is the sampling frequency of the time-domain signal.

    This input is available only if you wire one of the following data types to signal:

    • 1D array of double-precision, floating-point numbers
    • 1D array of complex double-precision, floating-point numbers
    • 2D array of double-precision, floating-point numbers
    • 2D array of complex double-precision, floating-point numbers

    Default: 1

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    real

    Real part of the FFT spectrum of the input signal.

    This output can return a cluster or a 1D array of clusters.

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    f0

    Start frequency, in Hz, of the spectrum.

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    df

    Frequency resolution, in Hz, of the spectrum.

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    real

    Real part of the FFT spectrum.

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    imaginary

    Imaginary part of the FFT spectrum of the input signal.

    This output can return a cluster or a 1D array of clusters.

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    f0

    Start frequency, in Hz, of the spectrum.

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    df

    Frequency resolution, in Hz, of the spectrum.

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    imaginary

    Imaginary part of the FFT spectrum.

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    error out

    Error information.

    The node produces this output according to standard error behavior.

    Standard Error Behavior

    Many nodes provide an error in input and an error out output so that the node can respond to and communicate errors that occur while code is running. The value of error in specifies whether an error occurred before the node runs. Most nodes respond to values of error in in a standard, predictable way.

    error in does not contain an error error in contains an error
    If no error occurred before the node runs, the node begins execution normally.

    If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as error out.

    If an error occurred before the node runs, the node does not execute. Instead, it returns the error in value as error out.

    Where This Node Can Run:

    Desktop OS: Windows

    FPGA: This product does not support FPGA devices


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