Abstract: A method of frequency tuning a piezoelectric device and apparatus for the implementation thereof. A piezoelectric device having at least one resonating function is formed by two metallized electrodes facing each other, on a face of a plate made of a piezoelectric material. An arranging step arranges the plate, fitted with the electrodes, in a tuning position in proximity to an ion source. Then, an exposing step exposes the plate to an ion flux produced by the source and the ions etch the metal. A measuring step measures the resonant frequency of the resonating function while the plate is in a tuning position. Finally, a raising step raises at least one electrode exposed to the ions to an adjustable bias voltage to control the rate at which the metal on the electrode is etched.

Abstract: The present invention relates to a process for controlled dissolution of a crystalline material consisting of a number of kinds of ions, in a solution containing a solvent for the crystalline material. Before dissolution, the solution contains at least two kinds of ions of the crystalline material. The molar concentration of ion of each kind is higher than zero and lower than the molar concentration of ion of each kind which the solution would have at saturation if it contained all of the constituent ions of the crystalline material, under the temperature and pressure conditions of the dissolution.

Abstract: In a device for thermal regulation of an enclosure comprising a temperature-measuring circuit which consists of a resistor bridge, of at least one heat-sensitive element on one bridge arm and of an amplifier, a control signal which is representative of the difference between the measured temperature of the enclosure and a reference temperature is delivered at the output of the amplifier. The absolute value of the control signal is adjusted by a negative feedback loop. A circuit for heating the enclosure is regulated by the temperature-measuring circuit and is constituted by at least one control transistor which delivers an adjustable heating current. The feedback loop of the output amplifier is mounted between the emitter resistor of the control transistor and the inverting input of the amplifier.

Abstract: A piezoelectric resonator (1) consists of a piezoelectric reed (2) encased in a housing composed of a cap (7) and a base (8). The resonator (1) is placed in a thermostatically controlled containment (10). The thermostatically controlled containment (10) consists of an inner cell (40) which is screwed into an outer cell (30). These cells (30, 40) each possess sides (34, 44) and a bottom (35, 45). A thermal seal (16) is inserted between the bottom (35) of the outer cell (30) and the bottom (45) of the inner cell (40). The cap (7) of the resonator is soldered over its entire outer surface to the sides (44) and to the bottom (45) of the inner cell (40). The thermostatically controlled containment (10) is placed in a secondary containment (21). A narrow space (22) separates the two containments (10, 21), and the surface of the contact between the two containments is as small as possible. The invention is used for ultrastable on-board oscillators.

Abstract: In a device for thermal regulation of an enclosure comprising a temperature-measuring circuit which consists of a resistor bridge, of at least one heat-sensitive element on one bridge arm and of an amplifier, a control signal which is representative of the difference between the measured temperature of the enclosure and a reference temperature is delivered at the output of the amplifier. The absolute value of the control signal is adjusted by a negative feedback loop. A circuit for heating the enclosure is regulated by the temperature-measuring circuit and is constituted by at least one control transistor which delivers an adjustable heating current. The feedback loop of the output amplifier is mounted between the emitter resistor of the control transistor and the inverting input of the amplifier.

Abstract: A temperature-compensated piezoelectric oscillator of high-spectral purity, capable of being controlled in frequency, consists of a compensation circuit, a processing circuit, a phase-shifting circuit, containing the piezoelectric resonator, and an oscillating circuit. To obtain high spectral purity, it is proposed to use a low-pass filter, placed between the compensation circuit and one of the inputs of the processing circuits, to process the signal coming from the compensation circuit. This filter eliminates the influence of the temperature noise coming from the compensation circuit. The invention can be applied to controllable frequency, temperature compensated piezoelectric oscillators where high spectral purity is sought.

Abstract: A dielectric filter with variable central frequency is provided comprising at least one dielectric resonator formed from a dielectric ceramic body covered with electrodes as well as electromagnetic input and output means for coupling the signal to and from the filter. According to the invention, the filter further comprises a variable capacity connected between the electrodes of the resonator, in a capacitive zone of said resonator, for continuously varying the central frequency of said filter.

Abstract: A cold-seal package affording resistance to high temperatures, comprising a base and a cover provided with an annular flange and so designed as to be brought into contact with each other in such a manner as to permit cold-sealing and encapsulation of an element to be protected. The base comprises a cup and a metallic mounting-plate, connector-pins being rigidly fixed to the mounting-plate and insulated with respect to this latter. The package is a vacuum-tight case comprising at least two columns located within the cover and rigidly fixed to the mounting-plate in order to suspend the element to be protected, and a ground pin brazed to the cup.

Abstract: A laser diode detection and optical pumping cesium resonator in which the frequency of the laser diode is made dependent on a signal delivered by a detector picking up the fluorescence light emanating from an interaction zone created just at the output of the cesium oven by the interaction of the cesium atom jet and a part of the light beam emitted by said detection diode. In particular, a laser diode detection and optical pumping cesium resonator having a cesium oven emitting a flow of cesium atoms, a resonating cavity in the flow path, a laser diode optical pump delivering a light beam into the atom flow between the cavity and the oven at a first interaction zone and a cesium resonance frequency generator. A detector for detecting fluorencence from a second interaction zone at the cavity output resulting from the interaction of the atom stream with a third laser. The detector delivering a signal representative of the second interaction to frequency control means to control the frequency of the generator.

Abstract: A method of fabricating a high-frequency piezoelectric resonator includes the steps of (a) forming a region of reduced thickness in a central portion of a quartz disk, a step zone being formed at the transition between the thinned region and the non-thinned region; (b) depositing a conductive tongue on the step so as to extend over a portion of the non-thinned region and over a portion of the thinned region; (c) mounting two lead attachments on the disk; and (d) depositing first and second electrodes on the disc, each electrode coupled to a respective one of the lead attachments, a portion of the first electrode being deposited on the conductive tongue.

Abstract: The invention concerns a very high frequency quartz oscillator. The feedback loop of the oscillator comprises a compensation network of a quartz at the frequency of the oscillator, and a low-pass filter eliminating the frequencies lower than that of the oscillator. A power divider having two branches allows to send the signal issuing from the feedback loop, on the one hand, to the amplifier input of the oscillator and, on the other hand, to the output amplifier. Two-port networks Q.sub.1 to Q.sub.6 match the impedances at the input and at the output of the amplifier of the oscillator, of the feedback loop and of the output amplifier.

Abstract: A piezoelectric resonator including a base, two conducting posts which pass through the base and a piezoelectric plate. The plate includes a central active zone which is surrounded by a peripheral zone. The two zones are connected by at least two bridges which define slits which separate the central zone from the peripheral zone. Each face of the central zone is covered with an adherent electrode which extends over one of the bridges to a part of the peripheral zone. Each of the electrodes is connected to one of the conducting posts through a conductive metal ribbon. Each of the metal ribbons bear on the inner part of the peripheral zone so that the ribbon is disposed substantially as an extension of the corresponding posts.

Abstract: A piezoelectric oscillator operating in the aperiodic or overtone mode comprising a first piezoelectric resonator having a resonance frequency at which the oscillator is to operate. One side of the first resonator is connected to ground, and the other side is connected through a second piezoelectric resonator to the base of a transistor. The second resonator has in common with the first resonator a mode at the resonance frequency, but its intrinsic quality factor is between 30 and 1000 times smaller than that of the first resonator. A capacitive divider bridge having a middle point is connected between the base of the transistor and ground. A third piezoelectric resonator having in common with said first resonator a mode at said resonance frequency, but whose intrinsic quality factor is of the same order of size as that of the second resonator, is connected between said middle point and the emitter of said transistor.

Abstract: A method and a device for regulating the heating of a thermostatically controlled enclosure of a quartz oscillator. During a first stage, the thermostatically controlled enclosure is exposed to an external temperature close to the maximum operating temperature and the frequency of the oscillator is measured. During a second stage, the thermostatically controlled enclosure is exposed to an external temperature close to the minimum temperature of the range and the difference between the frequency of the oscillator and the frequency previously measured is cancelled out by modifying the distribution of the powers dissipated by the heating elements of the thermostatically controlled enclosure. The heating of the enclosure is performed by a chain of voltage stabilizer semiconductor circuits connected in series, each of the circuits being traversed by a regulated heating current. The regulating of the heating action is performed by modifying the stabilized voltages of the circuits.

Abstract: A device having the function of compensating for the acceleration sensitivity of an oscillator of given nominal frequency comprises an acceleration-sensing element such as a filter which is capable of producing a signal having a nominal frequency equal to that of the oscillator to be compensated but, in respect of its nominal frequency, has higher sensitivity to acceleration than the oscillator to be compensated. The phase difference between the frequency of the oscillator and the frequency produced by the filter is compared in a mixer in order to extract the phase modulation induced by the acceleration. A follow-up control amplifier receives the output signal of the phase comparator and produces at its output a signal for correcting the oscillator.

Abstract: A piezoelectric oscillator of the Clapp type for operation in the overtone mode comprises a piezoelectric resonator having a C-mode resonance frequency at which the oscillator is designed to operate, the resonator being connected between the base of a transistor and ground. A capacitive voltage-dividing bridge is also connected between the base of the transistor and ground, the so-called midpoint of the bridge being connected to the emitter of the transistor. A quartz crystal and an inductance coil decoupled by a capacitor are placed between the emitter of the transistor and ground. The inductance coil and the capacitor form a high-pass filter for attenuating frequencies below the resonance frequency. The piezoelectric resonator is tuned to the mode B which is adjacent to the mode C in order to eliminate the unwanted mode B.

Abstract: A ceramic bonded structure with a high bonding strength has a first member of a ceramic, a ceramic-modified bonding layer formed on at least a bonding surface of the first member by a thermal treatment, a metal layer formed on the ceramic-modified bonding layer, and a second member of a ceramic or metal bonded with the first member through the metal layer.

Abstract: The subject of the invention is a high frequency bandpass amplifier with adjustable impedance, in particular for a high frequency quartz resonator. It includes a transistor T connected in common base the emitter of which is connected to ground by a resistive divider bridge (R.sub.2, R.sub.1) the mid-point of which forms the input of the amplifier. The collector of the transistor (T) is connected to ground by a parallel circuit (LC) having one inductive side (L) and one capacitive side (C), a mid-point of the inductive side (L) or of the capacitive side (C) forming an output (s.sub.1 or s.sub.2) of the amplifier (A). The base of the transistor is biased and connected to ground via a capacitor (C.sub.3) ensuring common base operation in the pass-band of the amplifier. The invention also relates to an oscillator of transmission type including such an amplifier and a resonator (1) connected between the input (e) and one output (s.sub.1 or s.sub.2) of the amplifier (A).

Abstract: The high-frequency piezoelectric resonator comprises a quartz plate or disk having a region of reduced thickness which forms a diaphragm and is joined to the remainder of the plate or disk by means of a zone forming a step. A conductive electrode extends from the exterior of the disk or plate to the center of the thinned region and is provided with a conductive tongue constituted by a metallic film-layer of controlled thickness and disposed in the stepped zone. The method involves formation of the disk or plate by ion machining whereas the electrodes and the conductive tongue are formed by the sputtering technique.

Abstract: To extend the variation range of a controlled frequency oscillator comprising a piezoelectric element, a lithium tantalate or lithium niobate element is used in parallel with which there is connected a linearization circuit comprising an inductance in series with a parallel circuit comprising a resistor and a capacitor.