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Introduction to Acoustics

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818 Part F Biological and Medical <strong>Acoustics</strong><br />

Part F 20.2<br />

0<br />

150µs<br />

22 kHz<br />

58 kHz<br />

100 kHz<br />

–30dB<br />

40 kHz<br />

65 kHz<br />

–20dB<br />

–10dB<br />

0dB 40°<br />

0 150µs<br />

0<br />

150µs<br />

0<br />

150µs<br />

30 kHz<br />

70 kHz<br />

120 kHz<br />

–30dB<br />

40 kHz<br />

70 kHz<br />

105 kHz<br />

–20dB<br />

–10dB<br />

0dB –40°<br />

30°<br />

–30°<br />

20°<br />

10°<br />

0°<br />

–10°<br />

–20°<br />

0<br />

0<br />

150µs<br />

150µs<br />

150µs<br />

0 150µs<br />

0<br />

150µs<br />

40°<br />

–30°<br />

30°<br />

–20°<br />

20°<br />

–10°<br />

0°<br />

10°<br />

0<br />

0<br />

150µs<br />

30 kHz<br />

108 kHz<br />

118 kHz<br />

45 kHz<br />

115 kHz<br />

72 kHz<br />

40 kHz<br />

122 kHz<br />

38 kHz<br />

120 kHz<br />

Fig. 20.10 The transmission beam pattern of a tursiops truncatus planes with the waveform of a click measured by 5–7<br />

hydrophones (after Au [20.39]) in the vertical and horizontal planes<br />

form having a maximum amplitude of unity. The source<br />

energy-flux density of the signal in dB can be expressed<br />

as<br />

⎛<br />

�T<br />

SE = 10 log ⎝ p(t) 2 ⎞<br />

dt⎠<br />

0<br />

⎛<br />

�T<br />

= 10 log(A) + 10 log ⎝ s(t) 2 ⎞<br />

dt⎠<br />

, (20.7)<br />

where T is the duration of the signal. Letting 2A ≈<br />

be the peak-<strong>to</strong>-peak sound pressure level, (20.4) can be<br />

0

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