| 摘要 |
A force or fluid pressure transducer comprises two plate-like crystals. The force is applied to the first of the two crystals in a direction generally along the crystal faces by two seatings situated at opposing edges of the crystal. An oscillating portion of this first crystal changes its frequency by an amount which is a very accurate measure of the force, providing the ambient temperature of the instrument remains constant. The present invention resides in a second crystal secured to the first crystal at particular force insensitive points, there being very small spacing between the two crystals. The second crystal sustains a negligibly small amount of the force and hence a similar oscillating portion of this second crystal undergoes negligibly small frequency change. Means are provided for adjusting the steady-state temperature behavior of one crystal with respect to that of the other in order to remove residual errors. The instrument output signal is formed by generating the difference frequency between the two crystals. This difference frequency changes only negligibly when the instrument is subjected to ambient temperature changes and hence provides superior performance to earlier inventions.
|
