BY Keyword (SPECTRA command)

By default, SPECTRA displays both frequency and period plots. You can use BY to produce only frequency plots or only period plots.

• BY FREQ indicates that all plots are plotted by frequency only. Plots by period are not produced.
• BY PERIOD indicates that all plots are plotted by period only. Plots by frequency are not produced.

Example

SPECTRA VARIABLES = SER01
  /PLOT=P S BY FREQ.

• This command plots both the periodogram and the spectral density estimate for SER01. The plots are shown by frequency only.