| 摘要 |
A system and method provide a low distortion hydrophone. A first known piezoelectric element is mounted so as to receive a pressure signal. A second piezoelectric element is provided with a means of receiving and enhancing the same pressure signal. Since a piezoelectric element is a capacitor, another capacitor is coupled in parallel with the second element to serve as a divider. The output voltage of the combination of the two elements is taken as the difference between the positive terminals of the two elements. Thus, the effect of the pressure enhancer and capacitance divider is to provide a difference in potential between the fundamentals from the two elements, while rendering the amplitude of the second harmonics equal. The two equal second harmonics cancel each other out at the output terminals, while retaining a useful fundamental for further signal processing. Further, the means of enhancing the pressure signal may comprise a cone-shaped baffle to amplify the pressure signal, or it may comprise a thinner diaphragm upon which the piezoelectric element is mounted to increase the flexing and thus the stress on the element. Also, more than two hydrophone elements may be coupled together to even more closely eliminate distortion over a wide pressure range.
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