Abstract: A technique for tracking changes in bias conditions of a microelectromechanical system (MEMS) device includes applying an electrode bias signal to an electrode of the MEMS device. The technique includes applying a mass bias signal to a mass of the MEMS device suspended from a substrate of the MEMS device. The technique includes generating the mass bias signal based on a target mass-to-electrode bias signal level and a signal level of the electrode bias signal.

Abstract: A shear-mode quartz resonator designed to mechanically oscillate at a predetermined frequency and electronic circuits for inhibiting oscillation of the shear-mode quartz resonator in response to externally applied mechanical forces which otherwise induce mechanical vibration of the shear-mode quartz resonator at frequencies significantly less than the predetermined frequency. The shear-mode quartz resonator includes a cantilevered quartz beam having relatively large metallic electrodes attached on opposite sides thereof, the relatively large metallic electrodes, in use, being coupled to an external oscillator circuit. The beam also has relatively smaller sense and rebalance electrodes attached on the same opposite sides of said quartz beam as said relatively large metallic electrodes. The relatively smaller sense and rebalance electrodes being coupled, in use, with said electronic circuits for inhibiting oscillation of the shear-mode quartz resonator in response to externally applied mechanical forces.

Abstract: A surface acoustic wave resonator includes a quartz crystal substrate with preselected Euler angles, and an IDT that is provided on the quartz crystal substrate, that includes a plurality of electrode fingers, and that excites a stop band upper end mode surface acoustic wave. Inter-electrode finger grooves are provided in the quartz crystal substrate between the electrode fingers in a plan view. When a wavelength of the surface acoustic wave is ?, a first film thickness of the electrode finger is H, and a first depth of the inter-electrode finger groove is G, and when a line occupation rate of convex portions of the quartz crystal substrate disposed between the inter-electrode finger grooves is ?g, and a line occupation rate of the electrode fingers disposed on the convex portions is ?e, the following relationships are satisfied 0.0407??G+H; and ?g>?e.

Abstract: The present invention is a piezoelectric crystal oscillator using parametric amplification to enhance the Q. Parametric amplification is accomplished by driving the same region of the crystal as used for the oscillator with an overtone of the crystal resonator.

Abstract: A surface acoustic wave resonator which can realize favorable frequency-temperature characteristics and suppress frequency variations is provided. The surface acoustic wave resonator includes a quartz crystal substrate with Euler angles (?1.5°???1.5°, 117°???142°, and 42.79°?|?|?49.57°), and an IDT that is provided on the quartz crystal substrate, includes a plurality of electrode fingers, and excites a stop band upper end mode surface acoustic wave, wherein inter-electrode finger grooves are provided between the electrode fingers in a plan view, and wherein if a line occupation rate of convex portions of the quartz crystal substrate disposed between the inter-electrode finger grooves is ?g, and a line occupation rate of the electrode fingers disposed on the convex portions is ?e, ?g>?e and 0.59<?eff<0.73 are satisfied in a case where an effective line occupation rate ?eff of the IDT is an arithmetic mean of the line occupation rate ?g and the line occupation rate ?e.

Abstract: To provide a technique capable of suppressing electric energy by a fundamental wave vibration and reducing phase noise in a piezoelectric oscillator using an overtone of a thickness shear vibration in a piezoelectric piece. An excitation electrode portion in an electrode 2 on one surface side of an AT cut crystal piece 1 is separated from each other in a direction perpendicular to a thickness shear vibration direction (in a Z?-axis direction) and separated portions are formed in parallel in a strip shape as divided electrodes 21, 22. The divided electrodes 21, 22 have end portions thereof connected to each other to be formed in an angular C-shape as a whole. An electrode 3 on the other surface side has strip-shaped excitation electrode portions 31, 32 formed at positions facing the first divided electrode 21 and the second divided electrode 22 on the one surface side respectively to be formed in an angular C-shaped electrode in the opposite direction.

Abstract: There is provided a resonance circuit using piezoelectric vibrator such as a quartz resonator, a coil, a capacitor, or an element equivalent to them in combination. When two resonance circuits having different resonance frequencies are combined, it is possible to configure an oscillation circuit and a filter capable of freely adjusting the frequency characteristic by utilizing the phenomenon that by changing the excitation current or voltage of the respective resonance circuits independently from each other, antiresonance frequency of the entire composite resonance circuit can be changed.

Abstract: A unit comprising a quartz crystal resonator vibratable in a flexural mode and having a base portion including a length less than 0.5 mm, and first and second vibrational arms connected to the base portion, at least one groove being formed in each of two of opposite main surfaces of each of the first and second vibrational arms, and an electrode being disposed on a surface of the at least one groove formed in each of the two of the opposite main surfaces of each of the first and second vibrational arms so that the electrode disposed on the surface of the at least one groove formed in each of the two of the opposite main surfaces of the first vibrational arm has an electrical polarity opposite to an electrical polarity of the electrode disposed on the surface of the at least one groove formed in each of the two of the opposite main surfaces of the second vibrational arm.

Abstract: The present invention provides a constant temperature oven type crystal oscillator for reducing the difference of frequency stability caused by controlling the temperature in the oscillator when detecting the change of the outside-air temperature and controlling the amount of generated heat of a heat source provided in the oscillator.

Abstract: A tuning fork type piezoelectric vibrating piece, comprising: a base unit having a base electrode for an external connection; a fork shaped arm unit extending from the base unit; a groove portion at least on a surface or a rear surface of the arm unit; a groove electrode on the groove portion; a side surface electrode on the arm unit without the groove portion; a first electrode connecting the base unit and the side surface electrode or the groove electrode; a second electrode connecting the groove electrode and the side surface electrode; and a side surface electrode set at a predetermined distance from the bottom of the fork part of the base unit. The piezoelectric vibrating piece may be packaged with a base electrode connected to an external output terminal. The piezoelectric oscillator may have an amplifier circuit and a feedback circuit with a resonant element determining the resonant frequency.

Abstract: A balanced crystal oscillator circuit comprising: a piezoelectric element Xtal (207; 215; 222,221; 313); a first oscillator subcircuit (202; 210; 218; 302) incorporating a transistor (204;212;220;304); and a second oscillator subcircuit (201;209;217; 301) incorporating a transistor (203; 211; 219; 303); wherein the transistors each have different types of transistor terminals (C,B,E; D;G;S), and wherein the oscillator subcircuits are configured with at least three interconnections. Each interconnection comprise a pair of like type of transistor terminals; wherein a first of said interconnections constitutes a connection to a ground reference (gnd); a second of said interconnections is via a first resonator element (207;215;223;313); and a third of said interconnections is via a second resonator element (208;216;224;314); said first and second circuits are arranged to interact by means of said first and second resonator elements to form a balanced oscillator signal.

Abstract: A micro-electromechanical system (MEMS) comprises a substrate incorporating an oscillatory ring, forcing electrodes for driving the ring into resonance, and sensing electrodes providing an electrical output signal dependent on oscillation of the ring as a result of such forcing and any externally applied force. A positive feedback circuit is provided for feeding back a signal dependent on the output signal of the sensing electrodes to the forcing electrodes in order to sustain oscillation of the ring. The use of positive feedback to drive the forcing electrodes in order to sustain oscillation of the ring is highly advantageous in such an application since it produces a system which exhibits very low phase noise of a magnitude considerably less than the phase noise experienced in use of a phase-lock loop circuit to sustain oscillation.

Abstract: In the method, following an operating point determination of the quartz resonator circuit, a substitution of the equivalent circuit diagram of the quartz resonator by an independent current source is implemented with the initial, previously determined amplitude of the current of the dynamic arm of the quartz resonator. The dynamic equilibrium state is determined for this circuit arrangement with firing methods or methods of harmonic balance. After a resubstitution of the current source by the equivalent circuit diagram of the quartz resonator, a transient analysis is implemented for the dynamic equilibrium state. This method is iteratively implemented as long as the identified growth rate lies above a prescribable barrier.

Abstract: An electrical circuit for reliably starting the oscillation of an oscillator comprising a cylindrical piezoelectric body on which an exciting electrode, a feedback electrode which causes an oscillation, and an electrode for detecting an angular rate are mounted. The electrical circuit includes an exclusive OR gate for detecting a phase difference between an exciting voltage and a voltage developed at the feedback electrode, a circuit for integrating an output voltage from the gate and a band pass filter having its resonant frequency shifted in proportion to a voltage from the integrating circuit. The band pass filter is effective to provide an automatic adjustment of a phase difference of a voltage, which is actually fed back to the exciting electrode, with respect to a voltage developed at the feedback electrode.

Abstract: An angular velocity detector circuit composed of: an oscillator circuit including an inverting amplifier connected between a driving electrode of a quartz crystal and an electrode for detecting an electric field generated in the quartz crystal by a Corioli's force when the quartz crystal is rotated; a differential amplifier circuit connected at its input terminals to the detecting electrode of the quartz crystal; a detector circuit which receives the output from the differential amplifier circuit and using the output from the oscillator circuit as detection signals; and an output amplifier circuit which receives the output from the detector circuit.

Abstract: A preferred embodiment of a resonator embodying the invention comprises entially a resonating plate, an action electrode and a detection electrode, and a supporting base. The electrodes are placed facing symmetrical narrow edges of the plate, opposite vibration loops, and are coupled to the plate by capacitive, electrostrictive or piezoelectric effect according to the material of which the plate is comprised. A very wide range of elastic solid materials can be used to embody the resonating plate. The plate is attached to the supporting base at points corresponding to vibration nodes of the plate. The plate vibrates advantageously according to a contour mode called Lame mode. High coefficients of quality in the region of 10.sup.7 are obtained. The resonators embodying the invention can be easily integrated. To do so, the plate is e.g. embodied in silicon. Such a resonator is included in a high-stability oscillating loop comprising a phase shifter and an amplifier.

Abstract: A method of directly bonding a crystal to a crystal includes the steps of mirror-polishing the surfaces of the crystals and then rinsing them with a cleaning material and then affecting a baking operation and then bonding them together and thereafter annealing them within a temperature range where crystal crystallization is not transited in phase so that a further strong bonding force is obtained. A crystal resonator is obtained where electrodes are oppositely established across a ply crystal blank with at least two sheets of crystal blanks having a desired cut angle and a desired thickness being directly bonded so that the respective crystal axes intersect at the desired angles. The ply crystal blank may have a central portion which is either thicker or thinner than a surrounding portion.

Abstract: A crystal oscillator for generating an output oscillation whose frequency is maintained constant independently of the variation of temperature including a first quartz vibrator arranged in a heating unit which includes a thermostat and vibrating at a fundamental frequency, a second quartz vibrator arranged also in the same heating unit and vibrating at a third overtone frequency, a frequency multiplying circuit for multiplying the fundamental frequency by three, a frequency comparator for comparing the fundamental frequency multiplied by three with the third overtone frequency to derive a frequency difference which represents a temperature of the thermostat, and a temperature controlling circuit for controlling the temperature setting of the thermostat in accordance with the detected frequency difference. Any one or both of the fundamental and third overtone oscillations may be derived as an output oscillation.

Abstract: The temperature of a quartz crystal oscillator is determined by comparison of a pair of inharmonically related overtone oxcillations of the same vibrational type, e.g. a thickness shear mode, and of the same overtone order. The use of inharmonically related signals relaxes the contraints on crystal design. The technique may be employed in a crystal controlled frequency synthesizer to provide a feedback signal for maintaining constant output frequency.

Abstract: A crystal resonator with plural electrodes comprises a crystal piece, first, second and third pairs of electrodes. The crystal piece causes shear vibration. The first electrode pair is provided in the center of the crystal piece and coupled to a variable impedance. The second and third electrode pairs are provided on both sides of the first electrode pair. The second and third electrode pairs are electrically connected together and are coupled to an oscillation circuit.

Abstract: A 3-terminal oscillating element has a square plate-like piezoelectric body, first and second electrodes provided on one surface of the piezoelectric body and a common electrode provided on the other surface of the piezoelectric body. The piezoelectric body is polarized in one direction between the first and common electrodes and in the opposite direction between the second and common electrode. The 3-terminal oscillating element, when provided in place of a combination of 2-terminal oscillating element and two externally provided capacitors C.sub.1 and C.sub.2 in a Colpitts circuit, substantially satisfies the following equations: ##EQU1## wherein C.sub.01 is an electrostatic capacitance between the first electrode and the counter electrode, C.sub.02 is an electrostatic capacitance between the second electrode and the counter electrode, and n is an transformation ratio of an ideal transformer; and ##EQU2## wherein S.sub.1 and S.sub.2 are areas of first and second electrodes, respectively.

Abstract: A trapped energy piezoelectric resonator for oscillator and multiple resonator applications has a piezoelectric substrate with electrodes disposed on each of its major surfaces. These electrodes are further comprised of a plurality of electrically interconnected and acoustically coupled sub-electrodes. The resonant frequency of these resonators may be controlled by varying the separation and, therefore, the acoustic coupling between the sub-electrodes. This resonator may be used in the feedback loop of an oscillator circuit as the frequency determining element. It may also be used to provide a resonator on a substrate carrying resonators of significantly different frequency.

Abstract: An oscillator comprises plural electrodes formed on a piezoelectric vibrator, and the oscillation frequency is controlled by varying the duty factor of the pulses for switching an effective electrode area of the plural electrodes. The frequency-temperature characteristic of the oscillator is compensated by varying the duty factor of the switching pulses according to temperature variations.No trimmer condenser is needed, and the frequency-temperature characteristic is compensated over a wide temperature range.

Abstract: A feedback circuit for use in an oscillator has a piezoelectric oscillating unit constituted by a square plate-like piezoelectric body, first and second electrodes provided on one surface of the piezoelectric body and a common electrode provided on the other surface of the piezoelectric body. The piezoelectric body is polarized in one direction between the first and common electrodes and in the opposite direction between the second and common electrodes.

Abstract: An oscillator circuit including a flexural quartz crystal vibrator of the tuning fork type having an electromechanical coupling factor within the range of 2.5% to 3.5%. The vibrator is comprised of a quartz crystal element including a base portion and a pair of vibratable legs extending therefrom, and a pair of electrodes disposed on the quartz element for receiving alternating electrical signals of opposite polarity for effecting flexural vibration of the legs in response to the electrical signals. The quartz element is defined by a cutting angle within the range of zytw (0.degree.-10.degree.)/(10.degree.-30.degree.).

Abstract: The invention is a single crystal force transducer in which the crystal is simultaneously resonated in two different modes having substantially the same frequency-temperature characteristics and different frequency-force characteristics. The difference in the change between the two resonant frequencies with a force applied to the crystal is therefore a temperature compensated signal indicative of the applied force. In the preferred embodiment the two resonant modes are anharmonic modes having a plurality of antinodes angularly disposed to each other.

Abstract: A crystal controlled square wave oscillator requiring a minimum number of components, exhibiting high frequency stability, and operating at substantially a 50% duty cycle. A quartz crystal dual monolithic resonator is provided having a pair of signal electrodes and a reference electrode. The resonator is capable of oscillating in symmetric and anti-symmetric modes, points of minimum attenuation, the symmetric mode exhibiting a 180.degree. phase shift, and the anti-symmetric mode exhibiting a phase shift of 0.degree.. An integrated circuit logic gate is connected between the signal electrodes, the logic gate being of the type having low input and output impedances so as not to degrade the Q of the resonator. The logic gate provides a phase shift of 180.degree. or 0.degree. causing the resonator to oscillate in its symmetric or anti-symmetric modes, respectively, the gate switching between its two logic levels to produce a square wave output at the frequency of the excited mode.

Abstract: A piezo-electric tuning fork oscillation circuit including a piezo-electric tuning fork and amplifier units, such as ordinary audio frequency signal amplifier circuits employing transistors, between which amplifier units, a phase correction circuit comprising resistance and capacitance is inserted. In the phase correction circuit, the oscillation frequency coincides with the center frequency of the tuning fork over a wide frequency range with phase shift angle of the correction circuit being adapted to increase as the frequency increases, for producing stable oscillating frequency with possible maximum oscillation output.