Example (SPECTRA command) 

SPECTRA VARIABLES = HSTARTS
  /CENTER
  /PLOT P S BY FREQ.
  • This example produces a plot of the periodogram and spectral density estimate for series HSTARTS.
  • CENTER adjusts the series to have a mean of 0.
  • PLOT specifies that the periodogram (P) and the spectral density estimate (S) should be plotted against frequency (BY FREQ).