Generates a waveform that is the sum of integer cycle sine tones.


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Inputs/Outputs

  • cdbl.png amplitude —

    amplitude is the value that the sum of all the tones is scaled to and is the largest absolute value that the waveform contains. The default is –1.

    amplitude is useful when outputting the waveform to an analog output channel. If the maximum value that the hardware can output is 5 volts, set amplitude to 5. If amplitude ≤ 0, the scaling is not applied.

  • cbool.png reset signal —

    reset signal, if TRUE, resets the phase to the phase control value and the time stamp to zero. The default is FALSE.

  • cdbl.png start frequency —

    start frequency is the lowest tone frequency generated. This value must be an integer multiple of Fs/#s. The default is 10.

  • c1ddbl.png tone amplitudes —

    tone amplitudes is an array in which each element is a single tone amplitude. The size of this array determines how many tones are generated.

  • ci32.png seed —

    seed, when > 0, causes reseeding of the noise sample generator.

    seed is ignored if phase relationship is set to Linear.

  • cdbl.png delta frequency —

    delta frequency is the magnitude of the spacing between adjacent tone frequencies. delta frequency must be an integer multiple of Fs/#s. The default is 100.

    If start frequency is 100 Hz, delta frequency is ten, and the tone amplitudes array contains three elements, the tone frequencies generated are 100 Hz, 110 Hz, and 120 Hz.

  • cerrcodeclst.png error in (no error) —

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

  • cnclst.png sampling info —

    sampling info contains sampling information.

  • cdbl.png Fs —

    Fs is the sampling rate in samples per second. The default is 1000.

  • cdbl.png #s —

    #s is the number of samples in the waveform. The default is 1000.

  • cbool.png coerce frequencies? —

    If coerce frequencies? is TRUE, the specified tone frequencies will be coerced to the nearest multiple of Fs/n.

  • cu16.png phase relationship —

    phase relationship is the distribution of the phases of the sine tones. The phase distribution affects the Peak/RMS ratio of the overall waveform.

    0random—Each phase is chosen randomly between 0 and 360 degrees.
    1linear difference—The phase difference between adjacent frequency tones varies linearly from 0 to 360 degrees. This gives the best Peak/RMS ratio but might cause the signal to have periodic components within the period of the overall waveform.
    2linear phase—The phase varies linearly from 0 to 360 degrees.
  • imsdt.png signal out —

    signal out is the generated waveform.

  • idbl.png crest factor —

    crest factor is the ratio of the Peak voltage to the RMS voltage of signal out.

  • i1ddbl.png actual tone frequencies —

    actual tone frequencies are the tone frequencies generated after accounting for coercion, if coerce frequencies? is TRUE, and the Nyquist criteria.

  • ierrcodeclst.png error out —

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

    • The frequency domain representation of this waveform is a sequence of impulses at the specified tone frequencies and zero at all other frequencies. The number of tones is determined by the size of the tone amplitudes array. The sine tones are generated using the frequency, amplitude, and samples information. The phases of the tones are determined using the relationship specified in phase relationship. This raw array then is scaled so that the largest absolute value is equal to amplitude. Finally, the waveform is bundled. The X0 element of the waveform is always set equal to 0 and the delta X element is set equal to 1/Fs.

    Examples

    Refer to the following example files included with LabVIEW.

    • labview\examples\Signal Processing\Waveform Measurements\Multitone with Amplitudes.vi