
184 CHAPTER 10. PROJECT 1: GUITAR SPECIAL EFFECTS
We can infer many things from Figure 10.6. First, the number of stopbands is equal
to R/2; for example, when R = 5, we have two and “one half” stopbands in the magni-
tude response of the filter. For “cosine type” comb filters, the stopbands are located at
0.5(F
s
/R), 1.5(F
s
/R), 2.5(F
s
/R),..., and so on, however many fit between 0 and F
s
/2. For
“sine type” comb filters, the stopbands are located at 0, (F
s
/R), 2(F
s
/R), 3(F
s
/R),...,and
so on, however many fit between 0 and F
s
/2. Second, α effects the maximum value of the
magnitude; for example, for the common setting of α =1.0, the maximum magnitude is 2.0