Signal Processing Basics

• Cross Correlation
  • Homework 7
    • Plot the Cross Correlation of the 2 channels from Homework 6 and see if the peak is shifted from the middle, the number of samples you measured from the previous step.
      • Hints:
        • Functions -> Express -> Signal Analysis -> Conv & Corr -> Cross Correlation
        • This function requires that you extract the 2 channels from the DDT. To do this, use Functions -> Express -> Sig Manip -> From DDT -> Single Waveform -> Channel 0 and then again for Channel 1. Connect the outputs of these to the X and Y inputs.
        • Before you plot the Cross Correlation, extract the 1D array of scalars using the From DDT so that the X-Axis is in samples.
        • Look at the help on the Cross Correlation for details.
    • Plot the Spectrogram of Channel 0.
      • Hint: There is a good Spectrogram example that ships with LabVIEW. Go to Help -> Find Examples... and search for STFT -STFT Spectrogram Demo.vi. You can copy from this example and paste it into your code.
    • Create a subVI CalcCCPeak.vi that computes the relative delay between channels 0 and 1.