Page 43 - The Master Handbook Of Acoustics
P. 43
18 CHAPTER ONE
10
6
4
2
0
f 1 f 2 f 3 f 4 f 5 f 6 f 7
10
6
4
2
Amplitude-arbitrary units 0 f 1 10 f 2 f 3 f 4 f 5 f 6 f 7
6
4
2
0
f 1 f 2 f 3 f 4 f 5 f 6 f 7
Frequency
FIGURE 1-15
The spectral energy of a pure sinusoid is contained entirely at a single frequency. The triangular and square
waves each have a prominent fundamental and numerous harmonics at integral multiples of the fundamental
frequency. Random noise (white noise) has energy distributed uniformly throughout the spectrum up to some
point at which energy begins to fall off due to generator limitations. Random noise may be considered a mix-
ture of sine waves with continuously shifting frequencies, amplitudes, and phases.
