Returns the frequency, amplitude, and phase for each signal tone whose amplitude exceeds a specified threshold. Wire data to the time signal in input to determine the polymorphic instance to use or manually select the instance.


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Inputs/Outputs

  • cmsdt.png time signal in —

    time signal in is the time-domain waveform.

  • cenum.png export mode —

    export mode selects the source of the signal and spectrum to export to exported signals.

    0none—Fastest computation
    1input signal—Input signal only
    2detected signal—Multiple tone
    3residual signal—Signal minus tone
  • cdbl.png threshold —

    threshold specifies the minimum amplitude that each tone must exceed for this VI to extract it from time signal in.

  • ci32.png max num tones —

    max num tones specifies the maximum number of tones that this VI extracts. If you set max num tones to –1, this VI extracts all tones whose amplitude exceeds threshold.

  • cerrcodeclst.png error in (no error) —

    error in describes error conditions that occur before this node runs. This input provides standard error in functionality.

  • ci32.png output sorting —

    output sorting specifies the sorting order of the tones that this VI extracts.

    0increasing frequency
    1decreasing amplitude
  • icclst.png exported signals —

    exported signals contains the signals specified by export mode.

  • imsdt.png exported time signal —

    exported time signal is the waveform containing the exported time signal as selected by export mode.

  • icclst.png exported spectrum (dB) —

    exported spectrum (dB) is the spectrum of the exported time signal as selected by export mode.

  • idbl.png f0 —

    f0 returns the start frequency, in hertz, of the spectrum.

  • idbl.png df —

    df returns the frequency resolution, in hertz, of the spectrum.

  • i1ddbl.png dB Spectrum (Hann) —

    dB Spectrum (Hann) is the magnitude spectrum of the (Hanning) windowed input signal, expressed in dB relative to 1.0 Vrms^2 for input signals in units of volts (V).

  • i1dnclst.png multiple tone information —

    multiple tone information returns the frequency, amplitude, and phase of each tone that this VI extracts. Each element of the array is one single tone.

  • idbl.png detected frequency —

    detected frequency is the frequency of the detected single tone in Hz.

  • idbl.png detected amplitude —

    detected amplitude is the peak amplitude of the detected single tone.

  • idbl.png detected phase (deg) —

    detected phase is the phase of the detected single tone in degrees.

    Use the Wrap Angle VI to change the units of detected phase. Wire detected phase to the angle in input on the Wrap Angle VI, and select degree in, degree out or degree in, radians out for the angle units input.

  • ierrcodeclst.png error out —

    error out contains error information. This output provides standard error out functionality.

    • The input signal can be real or complex and single-channel, in the form of a waveform, or multichannel, in the form of an array of waveforms. If you wire an array of real waveforms to time signal in, LabVIEW selects the Extract Multiple Tone Information N Chan instance by default. If you wire an array of complex waveforms to time signal in, LabVIEW selects the Extract Multiple Tone Information N Chan (CDB) instance by default.

    A real multiple tone signal can be expressed as shown in the following equation:

    where Ai, fi, and φi are the amplitude, frequency, and phase, respectively, of the ith tone of a multiple tone signal with N tones and Fs is the sample rate in samples per second of the input waveform signal.

    A complex multiple tone signal can be expressed as shown in the following equation:

    where Ai, fi, and φi are the amplitude, frequency, and phase, respectively, of the ith tone of a multiple tone signal with N tones and Fs is the sample rate in samples per second of the input waveform signal.

    For a real signal, the frequency range is (min frequency, max frequency) = (0, Fs/2). For a complex signal, the frequency range is (min frequency, max frequency) = (–Fs/2, Fs/2).

    Examples

    Refer to the following example files included with LabVIEW.

    • labview\examples\Signal Processing\Waveform Measurements\Complex Multi-Tone Measurements.vi