用兩幅圖簡單說明了audio signal processing的根本

Source-filter model and the corresponding spectra

人聲發音過程與與頻譜的對應


A BEGINNER'S GUIDE TO DIGITAL SIGNAL PROCESSING
http://www.analog.com/en/processors-dsp/content/beginners_guide_to_dsp/fca.html

THE SCIENTIST & ENGINEER'S GUIDE TO DIGITAL SIGNAL PROCESSING
http://www.analog.com/en/processors-dsp/learning-and-development/content/scientist_engineers_guide/fca.html