of Microprocessors

MUSIC SYNTHESIS PRINOPLES 29
fundamental. Another suggests that all of the remaining component frequencies
are ascertained, and the missing fundamental frequency is "computed"
from them. .
Nonrepeating Wavefonns
With the basics of definitely pitched sounds with repeating waveforms
in hand, lee's examine more closely the last three waveforms in Fig. 1-2. As
mentioned earlier) waveform C does not repeat but does have a pitch sense in
relation to other similar sounds. Its spectrum is shown in Fig. 1-8B. Note
that the sine wave component frequencies are not integral multiples of some
fundamental frequency. This is the main reason that the waveform does not
repeat and that it does not have an absolute pitch. However, since a small
number ofcomponent frequencies relatively far from each other are involved,
the sound is pleasing to hear, and the waveform trace is not unduly complex.
Actually, the statement about the waveform never repeating needs to
be qualified a bit. If all of the frequencies are rational numbers it will repeat
eventually. If one of the frequencies is irrational, such as 7T kHz, however,
the waveshape will indeed never repeat. At the moment, the presence or
1.0
O.B
1.0,
\
I I
~ 0.6 \
:)
r- \
::::i
~ 0.4
~.34