Fourier Series Multiple Fundamentals.
Cuthbert Nyack
Some signals may have many components, all periodic, whose frequencies may not be related to
one another. In these cases, it can be very laborious to identify the different frequencies using the
Fourier Series.
The plot above shows a signal consisting of 7 periodic signals with frequencies from 1
to 8.2Hz but not all of the same amplitude.
The simplest approach to finding the frequencies in this case is to use the Fast Fourier
Transform (FFT). This will be described later, here only a typical signal is illustrated.
The above plot shows an FFT spectrum for the set of 7 sinusoids, the frequencies of which
are indicated at the top. Notice there is no obvious relationship between the frequencies.
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COPYRIGHT © 1999 Cuthbert A. Nyack.