Abstract: The invention provides a piezoelectric bar resonator of small dimensions operating in the thickness shear mode and employing a minimum of separate and distinct elements. The resonating element 1 and its support 2 are blanked from a thin slab of piezoelectric material in a manner to provide a single piece of which the central portion forms the bar resonator and the peripheral portion constitutes a frame-work support. The two portions remain attached at at least one end of the bar. Planar or flattened cap type cover members 8 are fixed to frame 2. The invention may be applied where piezoelectric bar resonators of extremely small dimensions are required.

Abstract: An electronic component comprising at least one piezoelectric resonator and a process for mass production thereof include the superpositioning of n (n.gtoreq.1) layers having one or several cut outs defining m (m.gtoreq.1) resonating elements. Such layers are separated by n-1 intermediate layers in which are provided openings forming frames for the resonating elements. Two terminal layers providing covers in which are arranged blind cavities corresponding to the frames cover the assembly. The resonating elements are provided with electrodes and the layers are fixed to one another by welding together of metallization layers. The component may be used as an individual resonator or as a multiple channel filter.

Abstract: A piezo electric resonator member is cut from a quartz crystal in a rotated -orientation and arranged for vibration in a thickness shear mode, the member being in the form of a bar elongated along either the X-axis or the Z'-axis having rectangular cross sections in planes parallel respectively to the XZ'- and Y'Z'-planes or XZ'- and XY'-planes. It is provided with metallized layers to serve as electrodes confined to a central zone of the surfaces running in the same direction as the XZ'-plane. The ends of the bar serve as support points.

Abstract: This specification describes a rectangular quartz crystal which has been igned with specific length-width-thickness ratios whereby vibration takes place in the thickness shear mode strongly coupled with flexural vibrations. The choice of the specific ratios permits an improved performance insofar as dynamic capacitance range, temperature dependent variations of frequency and finally quality factor are concerned. The dimensions and proportions make the crystal suitable for use as a high frequency time piece resonator.

Abstract: Two frequencies to be compared are applied to two inputs of a flip-flop. output of the flip-flop is fed to a low pass filter and the output of the filter is a saw tooth voltage proportional to the phase difference between the two frequencies. Differentiation of the saw tooth voltage yields a voltage proportional to the difference between the two frequencies. A threshold circuit is provided for sensing the output voltage of the filter to control a flip-flop which in turn reverses the phase of one of the frequency signals and disconnects the output of the differentiator from a capacitive storage circuit.

Abstract: Apparatus for automatically adjusting the frequency of a piezoelectric reator in the form of a bar or plate includes circuitry for applying a voltage to the resonator to cause it to resonate, measuring the frequency of the resonator continuously during a frequency adjusting cycle, continuously comparing the measured frequency with a desired frequency to obtain a difference frequency value, storing the difference frequency value at the beginning of the adjusting cycle, deriving from the difference frequency value a threshold value equal to one-half of the difference frequency value, comparing the threshold value with the frequency difference value, removing material by a sand blast from a first extremity of the resonator as long as the difference frequency value is greater than the threshold value and thereafter removing material from the other extremity of the resonator until the difference frequency value is nil.

Abstract: A process for automatically adjusting the frequency of a piezoelectric reator in the form of a bar or plate includes the steps of applying a voltage to the resonator to cause it to resonate, measuring the frequency of the resonator continuously during a frequency adjusting cycle, continuously comparing the measured frequency with a desired frequency to obtain a difference frequency value, storing the difference frequency value at the beginning of the adjusting cycle, deriving from the difference frequency value a threshold value equal to one-half of the difference frequency value, comparing the threshold value with the frequency difference value, removing material by a sand blast from a first extremity of the resonator as long as the difference frequency value is greater than the threshold value and thereafter removing material from the other extremity of the resonator until the difference frequency value is nil.