The RATS Software Forum

I use band-pass filter to isolate high frequency and medium frequency from a series.
Then how can I draw spectral density of them in one graph?

I've attached a revised version of spectrum.src which allows you to save the computed spectrum (the 0 to pi part) using the option

SPECTRUM=series for spectrum.

You can use the @spectrum to generate both series, then use the same basic code as at the end of the spectrum procedure to graph the two on the same SCATTER instruction.