| 摘要 |
In order to simplify the process for milling/grinding the piezoelectric element, in the sense of eliminating the need firstly to mill/grind it roughly then, after measuring the frequency, to perform a fine matching milling/grinding operation, the device comprises a milling device (20) controlled by transistors (18, 19) the operation of which is conditioned by a comparator (17). The latter compares signals set up respectively by two groups of amplifiers, converters (13, 15; 14, 16) connected to the outlet of two filters (11, 12) supplied by frequencies picked up on the piezoelectric element as it is being milled. These filters give response curves in the field of the natural frequency of the piezoelectric element, and they are arranged to present, at the frequency desired by the quartz oscillator, the same attenuation coefficient value, whilst for the other values of frequency the coefficients of the two filters are different. This arrangement makes it possible to conduct one and the same milling/grinding operation until the desired natural frequency of the piezoelectric element is exactly reached, the manufacture of which element is thus simplified and made less expensive. The device is particularly suited to milling/grinding large batches of small quartz piezoelectric elements. <IMAGE>
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