| 摘要 |
<p>A vibratable element whose resonant frequency changes in accordance with an external source of variable applied pressure, has an inner cavity in fluid communication with the source of applied pressure, so that variations therein produce corresponding changes in the internal pressure of the cavity. Increases in this internal pressure cause the flexible walls surrounding the cavity to expand outwardly, thereby increasing the mechanical stiffness of the element. The increased stiffness produces a corresponding increase in the resonant frequency. Conversely, a decrease in pressure allows the walls to slacken and reduce the overall stiffness of the element. A linear relationship exists between changes in applied pressure and changes in the resonant frequency, over an appreciable range of pressures. An optical scheme detects the frequency, and conventional electronics correlate the frequency to the corresponding pressure, or to another physical variable represented by the applied pressure.</p> |
