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Exercises

  1. A sound has fundamental 440. How could it be ring modulated to give a tone at 110 Hz with only odd partials? How could you then fill in the even ones?

  2. What carrier and modulation frequencies would you give a two-operator FM instrument to give frequencies of 618, 1000, and 2618 Hz? (This is a prominent feature of Chowning's Stria [DJ85].)

  3. Suppose you wanted to make FM yet more complicated by modulating the modulating oscillator, as in:

    \begin{displaymath} \cos( \omega_c n + a \cos( \omega_m n + b \cos( \omega_p n ))) \end{displaymath}

    How would the spectrum differ from that of the simple two-modulator example (section 5.5.7)?


msp 2003-08-09