224results about "Apparatus using electrochemical resonators" patented technology

A time base including a resonator (4) and an integrated electronic circuit (3) for driving the resonator into oscillation and for producing, in response to the oscillation, a signal having a determined frequency. The resonator is an integrated micromechanical ring resonator supported above a substrate (2) and adapted to oscillate in a first oscillation mode. The ring resonator includes a free-standing oscillating structure (6). Electrodes (100, 120; 130, 150) are positioned under the free-standing oscillating structure in such a way as to drive and sense a second oscillation mode in a plane substantially perpendicular to the substrate and having a resonant frequency which is different from the resonant frequency of the first oscillation mode, a frequency difference between the resonant frequencies of both oscillation modes being used for compensating for the effect of temperature on the frequency of the signal produced by the time base.

The present invention is a method for adjusting the resonant frequency of a mechanical resonator whose frequency is dependent on the overall resonator thickness. Alternating selective etching is used to remove distinct adjustment layers from a top electrode. One of the electrodes is structured with a plurality of stacked adjustment layers, each of which has distinct etching properties from any adjacent adjustment layers. Also as part of the same invention is a resonator structure in which at least one electrode has a plurality of stacked layers of a material having different etching properties from any adjacent adjustment layers, and each layer has a thickness corresponding to a calculated frequency increment in the resonant frequency of the resonator.

An automatic temperature compensated real-time clock (RTC) chip includes a clock portion having a crystal oscillator block including crystal compensation circuitry adapted to be coupled to a crystal. The crystal compensation circuitry includes a non-linear capacitor DAC including a plurality of load capacitors, wherein the load capacitors have respective switches which switch respective ones of the load capacitors to change a parallel resonance frequency (fp) generated by the oscillator block. The capacitor DAC is arranged so that Analog Trimming (ATR) bits received cause an arrangement of the switches to provide a non-linear change in overall load capacitance to result in a linear relationship between fp and the ATR bits. A temperature sensor block is coupled to the crystal for measuring a temperature of at least the crystal. An A/D converter is coupled to the temperature sensor for outputting a digital temperature signal representative of the temperature of the crystal. A DSP engine receives the digital temperature signal and calculates frequency correction needed to correct for frequency inaccuracy and determines a bit sequence including the ATR bits appropriate to achieve the frequency correction.

A low power oscillator having fast start-up times. The low power fast starting oscillator uses an oscillator circuit having an input and an output for generating a signal of a desired frequency. A start-up detect circuit is coupled to the output of the oscillator circuit for detecting when the oscillator circuit has reached steady state operation and for generating a start-up circuit output signal which adjusts the gain of the oscillator circuit when steady state operation has been reached by the oscillator circuit. A noise generator is coupled to the input of the oscillator circuit and to the start-up detect circuit for inputting a noise pulse into the oscillator circuit. The noise pulse is used for biasing the input of the oscillator circuit to approximately an optimal bias voltage level. The noise generator is further used for sending an enable start-up detect signal to the start-up detect circuit to activate the start-up detect circuit. A prestress circuit is coupled to the input and to the output of the oscillator circuit for prestressing a piezoelectric resonator of the oscillator circuit to shorten start-up times of the oscillator circuit. The prestress circuit is further used for sending an enable noise generator signal to the noise generator to activate the noise generator.

A method for generating a temperature-compensated timing signal that includes counting, within an update interval, a first number of oscillations of a first micro-electromechanical (MEMS) resonator, a second number of oscillations of a second MEMS resonator and a third number of oscillations of a digitally controlled oscillator (DCO), computing a target DCO count based on the first number and second number of oscillations, computing a loop error signal based on the target DCO count and the third number of oscillations, and modifying an output frequency of a temperature-dependent (DCO) timing signal based on the loop error signal. The duration of the update interval may also be modified based on temperature conditions, and the update interval may also be interrupted and the output frequency immediately adjusted, if a significant temperature change is detected. Thus, dynamic and precise temperature compensation is achieved that accommodates constant, slowly changing, and rapidly changing temperature conditions.

An oscillator circuit is disclosed which can be formed using discrete field-effect transistors (FETs), or as a complementary metal-oxide-semiconductor (CMOS) integrated circuit. The oscillator circuit utilizes a Pierce oscillator design with three inverter stages connected in series. A feedback resistor provided in a feedback loop about a second inverter stage provides an almost ideal inverting transconductance thereby allowing high-Q operation at the resonator-controlled frequency while suppressing a parasitic oscillation frequency that is inherent in a Pierce configuration using a “standard” triple inverter for the sustaining amplifier. The oscillator circuit, which operates in a range of 10–50 MHz, has applications for use as a clock in a microprocessor and can also be used for sensor applications.

An oscillator includes a reference voltage generator, an oscillation element configured to oscillate by either a drive voltage or a drive current and output an oscillation signal, a peak hold element configured to detect a peak level of the oscillation signal for output; and a controller configured to increase or decrease the drive voltage or drive current in accordance with the reference voltage generated by the reference voltage generator and the peak level output from the peak hold element.

The Colpitts circuit is configured so that an equivalent capacitance of the voltage-dividing first and second capacitors connected in series through the output of the transistor amplifier is variable under the condition that the ratio of the capacitance of the first capacitor to that of the second capacitor is kept unchanged at a prescribed value. The first and second capacitors are, as a whole, configured as a matrix of elemental capacitors with 2 rows and a plural number n of columns, an array of the elemental capacitors in the first row being allotted to the first capacitor and an array of the elemental capacitors in the second row being allotted to the second capacitor. Two elemental capacitors in each column j (j=1, 2, . . . n) are connected in series and the ratio of the capacitance of the elemental capacitor corresponding to the 1j element of the matrix to the capacitance of the elemental capacitor corresponding to the 2j element has the prescribed value. The Colpitts circuit further has a first switch and a second switch allotted to each of the columns. Each of the elemental capacitors allocated to the first row is connected to the control electrode of the transistor amplifier through the first switch, and the junction of the two elemental capacitors allocated to each column is connected to the output of said transistor amplifier through the second switch. The first and second switches are operated synchronously for every column.

A crystal oscillator operates at the third overtone of the crystal's fundamental frequency. A value of a shunt resistor between the two phase-shift leg nodes is chosen so that the absolute value of the product gm×(Xc1)×(Xc2) is greater than the effective reactance of the crystal, where gm is the gain of the amplifier attached to the phase-shift legs, and Xc1 and Xc2 are the effective capacitive reactances of phase-shift legs at nodes X1 and X2. The third overtone is doubled by a multiplier and the final output filtered to remove the third overtone and select a frequency six times the fundamental frequency. A pair of Colpitts or Pierce amplifier half circuits is attached to the phase-shift leg nodes. The leg nodes can be capacitively isolated from Pierce-amplifier circuit nodes to improve start-up. Frequency doubling can be performed by summing currents from the two oscillator half circuits.

A crystal oscillator circuit includes: a crystal resonator circuit, generating an oscillation signal; an inverting amplification circuit, whose first amplifier input end is coupled to receive the oscillation signal, in which an inverting amplifier outputs an inverting amplified output signal; a bias circuit, having a bias circuit input end and a bias circuit output end, in which the bias circuit output end generates a bias circuit output signal controlled by the bias circuit input end, and the bias circuit output signal is coupled to a second amplifier input end; and a peak detection circuit, comparing the inverting amplified output signal with a reference signal, regulating a peak detector output signal, and feeding the peak detector output signal into the bias circuit input end, in which the bias circuit includes a self-adjusting circuit, for isolating a power supply from a second input end of the inverting amplifier.

A crystal oscillation circuit that is capable of operating stably with a low power consumption includes a signal inversion amplifier and a power control circuit that controls the power voltage of this signal inversion amplifier in accordance with an oscillation output. The power control circuit includes a power voltage generation circuit that outputs a plurality of power voltages of different values; a determination control portion that determines the optimal value of the power voltage to be applied to the signal inversion amplifier, based on the oscillation output; and a multiplexer that controls the switching of the power voltage applied to the signal inversion amplifier from the power voltage generation circuit, based on the result of that determination.

A temperature compensated resonator including a body used in deformation, the core of the body including a first material. The body includes at least a first and second coating allowing the resonator to have substantially zero first and second order temperature coefficients. The temperature compensated regulator can be used in the field of time and frequency bases.

This invention relates to a crystal oscillation circuit that oscillates stably with a low power consumption. This crystal oscillation circuit comprises an inverting amplifier, a crystal oscillator, and a feedback circuit that inverts the phase of an output from this inverting amplifier and feeds it back as an input. The sum of the absolute value of the threshold voltage of a first semiconductor switching element and the absolute value of the threshold voltage of a second semiconductor switching element is set to be greater than or equal to the absolute value of the potential difference between first and second potentials, when said inverting amplifier includes the first and second semiconductor switching elements.

A voltage-controlled crystal oscillator (VCXO) has variable load capacitors on the crystal nodes. The variable load capacitors are p-channel or n-channel transistors with their source and drain nodes connected to a crystal node. The gates are driven by an input voltage that is generated from a full-swing control voltage by a voltage conversion circuit. The input voltage has a half-swing of only half of the power-supply voltage, or VDD/2. The input voltage driving n-channel capacitors swings from VDD to VDD/2, which is just above the source voltage of VDD/2 on the crystal node and ensures that the n-channel capacitors remain on for most of the range. A series of resistors can divide the input voltage into a series of differing voltages that drive gates of multiple n-channel capacitors that have their source/drains connected in parallel to the crystal node. Capacitance increases as an n-channel capacitor channel turns on.

In an apparatus using optically excited atomic media, such as an atomic frequency standard, a source providing a controlled emission of light for exciting the D₁ and/or D₂ resonance lines of an alkali gas, such as rubidium or cesium, is controlled by an output generated by digital electronics from the light intensity signal of a light sensor for light transmitted by the alkali gas, an output for representing ambient temperature, and a light intensity-ambient temperature algorithm to substantially eliminate changes in light intensity due to light source aging for the purpose of reducing changes in temperature sensitivity of the apparatus as a function of time and the light-shift contribution to the frequency aging of the standard.

An oven-controlled oscillator includes a thermostatic oven having a heat source, a vibrator provided in the thermostatic oven, an oscillation circuit for generating an oscillation signal in response to an action of the vibrator, and a heat source control circuit. The heat source control circuit includes a sensor for detecting an internal temperature of the thermostatic oven, an operational amplifier for controlling current to flow through the heat source in response to a resistance value of the sensor so that the internal temperature of the thermostatic oven may be maintained at a predetermined preset temperature, and a feedback resistor for the operational amplifier. The feedback resistor includes a thermistor whose resistance value drops as the temperature rises, and the thermistor is thermally coupled to the thermostatic oven. Preferably, a quartz-crystal element is used as the vibrator.

An oscillator includes oscillator circuitry (8) including a transconductance stage (2) and a resonator (3). A comparator (10) produces first (CLK) and second (/CLK) clock signals which indicate the timing of positive and negative phases of a differential output signal (V_IN⁺-V_IN⁻) produced by the transconductance circuit in response to the resonator. A synchronous rectifier (14) converts the differential output signal to a current (I_RECT) in response to the first and second clock signals. A switched capacitor notch filter (15) filters the current in response to the first and second clock signals. A control current (I_CONTROL) which controls the transconductance of the transconductance circuit is generated in response to the notch filter. The resonator may be a MEMS resonator.