ABSTRACT
Central to the concept of filtering is the notion that a particular signal (i.e., a function of time f(t)) has a frequency content. This is a very familiar notion in music. A higher musical pitch means a higher frequency, and vice versa. Standard musical scales have been set up, including American Standard Pitch, adopted in 1936, International Pitch, adopted in 1891, and the Scientific or Just Scale (no flats or sharps).1 When at the beginning of a concert the oboe plays a note and the orchestra tunes to it, the players are tuning to “Concert A,” 440 Hz, if they are playing in American Standard Pitch.
