one can never read enough tutorials on signal processing.

Most could benefit from being modernized to use block diagram software like Scilab/Xcos. Learning is much quicker and more effective when there's an interactive hands-on component.

Everything is time series analyzable, so long as you wait long enough ;)

supplemental if you care about details

https://en.wikipedia.org/wiki/Joseph_Fourier

https://betterexplained.com/articles/an-interactive-guide-to...

http://hyperphysics.phy-astr.gsu.edu/hbase/Audio/fourier.htm...

Anybody want to figure out the year? Speaker Builder Magazine seems to have been an 80s thing...

This:

https://audioxpress.com/article/frequency-delay-dispersion

Lists it in references (at the very bottom of the page) as

  Bill Waslo, “Time, Frequency, Phase, and Delay,” Speaker Builder 7/96.

Excellent work! Added above. Thanks!