T. P. Traitement du Signal Maîtrise E.E.A. - LASC

6 SPTool: A Signal Processing GUI Suite
2 Open the Spectrum Viewer to analyze both of these spectra.
3 Print both spectra.
Creating a PSD Object From a Signal
1 Click on SPTool, or select SPTool from the Window menu of any active open
GUI. SPTool is now the active window.
2 Select the noise[vector] signal in the Signals list of SPTool.
3 Press Create in the Spectra list.
The Spectrum Viewer is activated, and a PSD object (spect1) corresponding
to the noise signal is created in the Spectra list. The PSD is not computed
or displayed yet.
4 Press Apply in the Spectrum Viewer to compute and display the PSD
estimate spect1 using the default parameters.
The PSD of the noise signal is displayed in the display region. The
identifying information for the PSD’s associated signal (noise) is displayed
above the Parameters region.
The PSD estimate spect1 is within 2 or 3 dB of 0, so the noise has a fairly
“flat” power spectral density.
5 Follow steps 1 through 4 for the bandlimited noise signal blnoise to create
a second PSD estimate spect2.
The PSD estimate spect2 is flat between 750 and 1250 Hz and has 75 dB
less power in the stopband regions of filt1.
Opening the Spectrum Viewer with Two Spectra
1 Reactivate SPTool again, as in step 1 above.
2 Shift+click on spect1 and spect2 in the Spectra list to select them both.
3 Press View in the Spectra list to reactivate the Spectrum Viewer and
display both spectra together.
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