| 摘要 |
<p>The control incorporates circuits (6, 9, 10) to generate an electrical signal which contains a component which represents the natural frequency of the crystal while it is being ground. The arrangement further incorporates two filters (11, 12) with equal selective damping characteristics at a predetermined natural frequency of the crystal. Coincidence of the output signals of the two filters is determined in a circuit (17). The grinding process is stopped (18-20), if the two signal outputs, as determined in the circuit (17), are equal.</p> |
