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isNewDataReady

Check spectrum analyzer for new data

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Syntax

flag = isNewDataReady(scope)

Description

flag = isNewDataReady(scope) indicates whether the spectrum analyzer scope displays new spectral estimates. When logging spectrum analyzer data from the spectrumAnalyzer scope, use this function to ignore duplicate spectra from the getSpectrumData function.

example

Examples

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Open Script

Generate a discrete sine wave. Then display the sine wave signal using the Spectrum Analyzer. While the Spectrum Analyzer is running, save the spectrum data to a table. The Spectrum Analyzer does not update at every time step. To avoid saving that redundant spectrum data, use the isNewDataReady function.

wave = dsp.SineWave(Frequency=100,SampleRate=1000);
wave.SamplesPerFrame = 1000;
scope = spectrumAnalyzer(SampleRate=wave.SampleRate,...
    ViewType="spectrum-and-spectrogram");
data = [];

for ii = 1:250
    x = wave() + 0.05*randn(1000,1);
    scope(x);
    if scope.isNewDataReady
        data = [data;getSpectrumData(scope)];
    end
end

release(scope);

Show the first five rows in the table. You can see gaps in the simulation time in the data table. The missing rows indicate times where the Spectrum Analyzer was waiting for additional samples to update the spectrum. The isNewDataReady function prevented the script from saving that redundant data.

data(1:5,:)

ans =

  5x4 table

    SimulationTime       Spectrum           Spectrogram       FrequencyVector
    ______________    _______________    _________________    _______________

      {[0.9990]}      {1024x1 double}    {100x1024 double}    {1024x1 double}
      {[1.9990]}      {1024x1 double}    {100x1024 double}    {1024x1 double}
      {[2.9990]}      {1024x1 double}    {100x1024 double}    {1024x1 double}
      {[3.9990]}      {1024x1 double}    {100x1024 double}    {1024x1 double}
      {[4.9990]}      {1024x1 double}    {100x1024 double}    {1024x1 double}

Input Arguments

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Spectrum analyzer from which you want to save data, specified as a spectrumAnalyzer object.

Output Arguments

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Flag indicating new data, returned as one of these:

  • true –– The Spectrum Analyzer shows new data.

  • false –– The Spectrum Analyzer shows the same spectrum and no new data is available.

Version History

Introduced in R2017b

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See Also

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