46results about How to "High-frequency stability" patented technology

In method for manufacturing a quartz crystal tuning fork resonator capable of vibrating in a flexural mode, a quartz crystal wafer is etched in a first etching process to form a quartz crystal tuning fork base and quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. The quartz crystal wafer is etched in a second etching process different from the first etching process to form a groove having stepped portions in at least one of opposite main surfaces of each of the quartz crystal tuning fork tines. First electrodes having a first electrical polarity are disposed on the stepped portions of the grooves of respective ones of the quartz crystal tuning fork tines. Second electrodes having a second electrical polarity opposite to the first electrical polarity are disposed on side surfaces of respective ones of the quartz crystal tuning fork tines.

A quartz crystal unit has a quartz crystal tuning fork resonator capable of vibrating in a flexural mode of an inverse phase. The quartz crystal tuning fork resonator has a fundamental mode of vibration, a second overtone mode of vibration, a quartz crystal tuning fork base, and a plurality of quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. A merit value M2 for the second overtone mode of vibration of the quartz crystal tuning fork resonator is less than 30 so that the second overtone mode of vibration thereof is suppressed, the merit value M2 being defined by a ratio Q2 / r2, where Q2 and r2 represent a quality factor and a capacitance ratio of the second overtone mode of vibration, respectively, of the quartz crystal tuning fork resonator capable of vibrating in the second overtone mode.

A crystal oscillator with variable gain and variable output impedance inverter system includes an inverter, a variable impedance feedback circuit, connected between the output and input of the inverter, a crystal oscillator system, having a crystal with first and second electrodes connected across the input and output of the inverter; a serial variable impedance circuit connected between the inverter output and an electrode of the crystal and a control circuit for temporarily, during start up mode, increasing the impedance of the feedback circuit and decreasing the impedance of the serial circuit relative to the stationary mode impedances and then returning the feedback impedance to the lower impedance level and the serial circuit to the higher impedance level that promotes high frequency stability of the oscillator in the normal, stationary mode, of operation.

In a method for manufacturing a quartz crystal unit, a quartz crystal tuning fork resonator is formed by etching a quartz crystal wafer to form a quartz crystal tuning fork base and first and second quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. The quartz crystal tuning fork resonator has a piezoelectric constant e′12 within a range of 0.12 C / m2 to 0.19 C / m2 in the absolute value to drive the quartz crystal tuning fork resonator. An electrode is disposed on each of two of side surfaces of each of the first and second quartz crystal tuning fork tines so that the electrodes disposed on the side surfaces of the first quartz crystal tuning fork tine have an electrical polarity opposite to an electrical polarity of the electrodes disposed on the side surfaces of the second quartz crystal tuning fork tine. The quartz crystal tuning fork resonator is mounted on a mounting portion of a case.

A method for manufacturing a quartz crystal unit comprises forming a quartz crystal tuning fork resonator that is capable of vibrating in a flexural mode of an inverse phase and that has a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines connected to the quartz crystal tuning fork base. An electrode is disposed on each of two of side surfaces of each of the first and second quartz crystal tuning fork tines so that the electrodes of the first quartz crystal tuning fork tine have an electrical polarity opposite to an electrical polarity of the electrodes of the second quartz crystal tuning fork tine, a motional capacitance C1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator being greater than a motional capacitance C2 of a second overtone mode of vibration thereof.

In an electronic apparatus comprising a digital display portion and first and second oscillators comprising first and second oscillating circuits, each of the first and second oscillating circuits having a resonator, an amplifier, a plurality of capacitors, and at least one resistor, a mode of vibration of the resonator of the first oscillating circuit being the same as that of the resonator of the second oscillating circuit, an output signal being output from each of the first and second oscillating circuits, the output signal of one of the first and second oscillating circuits being a clock signal for use in operation of the electronic apparatus to display time information at the digital display portion.

The electronic apparatus comprises a display portion and a quartz crystal oscillator at least, and said electronic apparatus comprises at least two quartz crystal oscillators. Also, each of two quartz crystal oscillators of the at least two oscillators comprises a quartz crystal oscillating circuit having an amplification circuit and a feedback circuit. The feedback circuit is constructed by a flexural mode, quartz crystal tuning fork resonator or a width-extensional mode quartz crystal resonator or a thickness shear mode quartz crystal resonator and for example, the quartz crystal tuning fork resonator comprising tuning fork tines and tuning fork base that are formed integrally, is shown with novel shape and electrode construction. Also, the quartz crystal tuning fork resonator, capable of vibrating in a fundamental mode and having a high frequency stability can be provided with a small series resistance and a high quality factor, even when the tuning fork resonator is miniaturized. This is accomplished by grooves, groove dimensions and electrode construction on the tuning fork tines and / or tuning fork base of the quartz crystal tuning fork resonator. In addition, from a relationship of an amplification rate and a feedback rate, the quartz crystal oscillator having an output signal of a frequency of the fundamental mode vibration for the quartz crystal tuning fork resonator can be provided with the high frequency stability.

The electronic apparatus comprises a display portion and a quartz crystal oscillator at least, and said electronic apparatus comprises at least two quartz crystal oscillators. Also, each of two quartz crystal oscillators of the at least two oscillators comprises a quartz crystal oscillating circuit having an amplification circuit and a feedback circuit. The feedback circuit is constructed by a flexural mode, quartz crystal tuning fork resonator or a width-extensional mode quartz crystal resonator or a thickness shear mode quartz crystal resonator and for example, the quartz crystal tuning fork resonator comprising tuning fork tines and tuning fork base that are formed integrally, is shown with novel shape and electrode construction. Also, the quartz crystal tuning fork resonator, capable of vibrating in a fundamental mode and having a high frequency stability can be provided with a small series resistance and a high quality factor, even when the tuning fork resonator is miniaturized. This is accomplished by grooves, groove dimensions and electrode construction on the tuning fork tines and / or tuning fork base of the quartz crystal tuning fork resonator. In addition, from a relationship of an amplification rate and a feedback rate, the quartz crystal oscillator having an output signal of a frequency of the fundamental mode vibration for the quartz crystal tuning fork resonator can be provided with the high frequency stability.

A tire pressure monitoring system is capable of ensuring accuracy of the rate of transmission of data via wireless communications without an increase in the number of oscillators and an increase in the cost. The tire pressure monitoring system includes a tire pressure measuring module. The tire pressure measuring module has a microcomputer, an activation control circuit, a pressure sensor, a temperature sensor, a frequency divider, a transmitting circuit, and a battery. The microcomputer has a clock pulse generator, analog-to-digital converter circuits and a controller. The transmitting circuit has an oscillator circuit. The frequency divider divides the frequency of a carrier wave CW output from the oscillator circuit to generate a clock signal, and outputs the clock signal to the controller included in the microcomputer. The clock signal is used for the timing for outputting data to a data signal line DL. The clock signal for high precision data transmission can be generated without the need to provide an expensive oscillator in the microcomputer since the oscillator circuit is used in the transmitting circuit, and the clock signal used for data transmission by the microcomputer is generated by the inexpensive frequency divider.

In a method for manufacturing a quartz crystal unit, a metal film is formed on a quartz crystal wafer which is then etched to form a quartz crystal tuning fork resonator having first and second tines vibratable in flexural and fundamental modes. A groove is chemically etched in a first main surface of both tines such that a first surface of the groove is opposite a first side surface of the corresponding tine. The width of the groove is greater than a distance in the width direction from the groove first surface to the first side surface of the corresponding tine. An electrode is formed on each groove first surface and on the first side surface of both tines with the electrode on the groove first surface of the first tine having the same electrical polarity as the electrode on the first side surface of the second tine.

A quartz crystal unit comprising a quartz crystal tuning fork resonator capable of vibrating in a flexural mode of an inverse phase and having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines connected to the quartz crystal tuning fork base, an electrode being disposed on each of two of side surfaces of each of the first and second quartz crystal tuning fork tines so that the electrode disposed on each of two of the side surfaces of the first quartz crystal tuning fork tine has an electrical polarity opposite to an electrical polarity of the electrode disposed on each of two of the side surfaces of the second quartz crystal tuning fork tine, a motional capacitance C1 of a fundamental mode of vibration of the quartz crystal tuning fork resonator being greater than a motional capacitance C2 of a second overtone mode of vibration thereof.

The electronic apparatus comprises a display portion and a quartz crystal oscillator at least, and said electronic apparatus comprises at least one quartz crystal oscillator. Also, the at least one oscillator comprises a quartz crystal oscillating circuit comprising an amplification circuit and a feedback circuit. The feedback circuit is constructed by a flexural mode, quartz crystal tuning fork resonator or a length-extensional mode quartz crystal resonator and for example, the quartz crystal tuning fork resonator comprising tuning fork tines and tuning fork base that are formed integrally, is shown with novel shape and electrode construction. Also, the quartz crystal tuning fork resonator, capable of vibrating in a fundamental mode and having a high frequency stability can be provided with a small series resistance and a high quality factor, even when the tuning fork resonator is miniaturized. In addition, from a relationship of an amplification rate and a feedback rate, an output signal of the quartz crystal oscillating circuit having an oscillation frequency of the fundamental mode vibration for the quartz crystal tuning fork resonator can be provided with the high frequency stability.

In a quartz crystal unit, the unit comprising a quartz crystal tuning fork resonator having a quartz crystal tuning fork base, and first and second quartz crystal tuning fork tines, each of the first and second quartz crystal tuning fork tines having a first vibrational portion including a first width and a second vibrational portion including a second width greater than the first width, at least one groove being formed in at least one of opposite main surfaces of the first vibrational portion of each quartz crystal tuning fork tine, the first width of the first vibrational portion of each quartz crystal tuning fork tine being greater than 0.03 mm and less than 0.075 mm and the second width of the second vibrational portion of each quartz crystal tuning fork tine being greater than 0.04 mm and less than 0.23 mm.