Quartz Crystal Oscillator Research Articles

Investigating the impact of supply voltage fluctuations on phase noise in quartz crystal oscillators.

The impact of power supply voltage fluctuations on the phase noise of quartz crystal oscillators (XOs) remains an open issue. Currently, there is a lack of comprehensive analysis on this matter. This work presents a novel phase-noise drive sensitivity (PNDS) model for the XO to reveal its mechanism. This model based on five noise modulation processes demonstrates the distribution of the PNDS in the frequency domain clearly, and there exists a PNDS bandwidth fS that limits the supply voltage fluctuation, which is similar to the effect of the noise bandwidth of the classical Leeson model. Using the PNDS, we successfully predict the phase noise of a 10MHz oscillator under different supply voltage noises. In addition, experimental results show that the PNDS floor is determined by the phase modulation of the sustaining amplifier, while the amplitude-frequency effect of the resonator and the tuning of the diode often play crucial roles in the near-carrier PNDS.

The Interaction between Anesthetic Isoflurane and Model-Biomembrane Monolayer Using Simultaneous Quartz Crystal Microbalance (QCM) and Quartz Crystal Impedance (QCI) Methods.

The interaction between anesthetic Isoflurane (Iso) and model-biomembrane on the water surface has been investigated using quartz crystal microbalance (QCM) and quartz crystal impedance (QCI) methods. The model-biomembranes used were dipalmitoyl phosphatidyl choline (DPPC), DPPC-palmitic acid (PA) mixture (DPPC:PA = 8:2), DPPC-Alamethicin (Al) mixture (DPPC:Al = 39:1), and DPPC-β-Lactoglobulin (βLG) mixture (DPPC:βLG = 139:1) monolayers, respectively. The quartz crystal oscillator (QCO) was attached horizontally to each monolayer, and QCM and QCI measurements were performed simultaneously. It was found that Iso hydrate physisorbed on each monolayer/water interface from QCM and changed those interfacial viscosities from QCI. With an increase in Iso concentration, pure DPPC, DPPC-PA mixed, and DPPC-Al mixed monolayers showed a two-step process of Iso hydrate on both physisorption and viscosity, whereas it was a one-step for the DPPC-βLG mixed monolayer. The viscosity change in the DPPC-βLG mixed monolayer with the physisorption of Iso hydrate was much larger than that of other monolayers, in spite of the one-step process. From these results, the action mechanism of anesthetics and their relevance to the expression of anesthesia were discussed, based on the "release of interfacial hydrated water" hypothesis on the membrane/water interface.

Study of oscillation characteristics for quartz crystal oscillators based on equivalent multi‐physics model

AbstractIn recent years, high‐performance quartz‐crystal oscillators (XOs) for integrated circuits have been receiving considerable attention due to their featuring low voltage and high‐frequency stability. However, recent studies tend to focus solely on the impact of temperature as a single factor on crystal oscillator circuits, overlooking the circuit structure of the crystal oscillator itself. In this paper, a novel four‐parameter crystal model of XOs is detailed demonstrated, and analyzed to interpret typical XO oscillation characteristics at room temperature. The relationship between the RLC circuit and the oscillation was investigated. Meanwhile, the study delves into the various factors that influence oscillation behavior, paving the way for a comprehensive understanding of XOs' performance characteristics. temperature sweep simulations were induced to verify the theory and found that the parameter drift and thermal perturbation are close to the theory we proposed, which can be applied in temperature‐compatible XOs. The significance of this study lies not only in its contribution to the design and implementation of compact footprint XOs in the oscillator circuit platform but also in its provision of experimental evidence for fabricating wide temperature range compensated XO devices. The results show that the capacitance in the equivalent model of a crystal oscillator plays a dominant role in shaping the output waveform and exhibits relatively good temperature stability characteristics and serve as a valuable resource for engineers and researchers working on improving the performance and reliability of XOs, ultimately enabling the development of more advanced and efficient integrated circuits.

Analysis and design research of digital electronic clocks

A digital electronic clock stands as a pinnacle of modern timing technology, built on digital circuits that offer precise hour, minute, and second tracking and display capabilities. The evolution of integrated circuits, combined with the ubiquitous application of quartz crystal oscillators, has propelled the digital electronic clock into myriad sectors including science, transportation, and finance. These clocks, appreciated for their precision, clarity, stability, and other attributes, vastly differ from their mechanical predecessors. Absent of mechanical transmission devices, they promise longevity and exact timekeeping. Such digitization serves as the foundational technological support for crafting large machinery and precision tools. Delving into the intricacies of digital electronic clocks and broadening their utilization holds substantial real-world relevance. This discourse employs a top-down hierarchical circuit design approach, segmenting the comprehensive circuit into distinct modules. This method not only streamlines its configuration, rendering it user-friendly and legible, but also ensures that each segmented circuit operates as an autonomous entity. This modularity facilitates smoother simulations and circuit modifications, enhancing adaptability and efficiency.

Resonant X-ray excitation of the nuclear clock isomer 45Sc

Resonant oscillators with stable frequencies and large quality factors help us to keep track of time with high precision. Examples range from quartz crystal oscillators in wristwatches to atomic oscillators in atomic clocks, which are, at present, our most precise time measurement devices1. The search for more stable and convenient reference oscillators is continuing2–6. Nuclear oscillators are better than atomic oscillators because of their naturally higher quality factors and higher resilience against external perturbations7–9. One of the most promising cases is an ultra-narrow nuclear resonance transition in 45Sc between the ground state and the 12.4-keV isomeric state with a long lifetime of 0.47 s (ref. 10). The scientific potential of 45Sc was realized long ago, but applications require 45Sc resonant excitation, which in turn requires accelerator-driven, high-brightness X-ray sources11 that have become available only recently. Here we report on resonant X-ray excitation of the 45Sc isomeric state by irradiation of Sc-metal foil with 12.4-keV photon pulses from a state-of-the-art X-ray free-electron laser and subsequent detection of nuclear decay products. Simultaneously, the transition energy was determined as {mathrm{12,389.59}}_{+0.12left({rm{syst}}right)}^{pm 0.15left({rm{stat}}right)},{rm{eV}} with an uncertainty that is two orders of magnitude smaller than the previously known values. These advancements enable the application of this isomer in extreme metrology, nuclear clock technology, ultra-high-precision spectroscopy and similar applications.

Thin layer sonoelectrochemistry: Impact on slow heterogeneous electron transfer

In thin layer sonoelectrochemistry (TLS), constructive interference is established in a thin layer of electrolyte with a low power, ultrasonic quartz crystal oscillator (QCO). No cavitation, no temperature increase, and no impacts on mass transport are observed. In this first report of TLS experiments without cavitation, voltammetric morphologies are not disrupted. Interfacial electron transfer for three transition metal species are evaluated with established cyclic voltammetric diagnostics. For Ru(bpy)32+ with inherently fast (reversible) interfacial electron transfer, voltammograms are unchanged on sonication at 41 kHz. For Fe3＋ with slow heterogeneous electron transfer, interfacial rate increases with sonication, where increases in rate persist without diminution for minutes postsonication. For a cobalt phenanthroline probe, changes in voltammetric morphology at higher QCO intensity are consistent with chemical changes of ligand loss. Constructive interference in TLS imparts sound pressure to the electrode solution interface to increase electron transfer rates without mass transport disruption. TLS may provide means to electrocatalyze interfacial rates.

A Filter-Free Third Overtone Quartz Oscillator Based on Micromachining Technology.

This work investigates an AT-cut quartz crystal oscillator (XO) operating at its enhanced third overtone thickness shear (TS) mode while suppressing the fundamental TS mode by micromachining technology. A unique quartz plate structure has been proposed to alleviate the strong resonant signal from the first mode. A finite-element method (FEM) was used to characterize the first mode suppression while improving the performance of third overtone in terms of Q -factor and motional resistance ( Rm ) of the proposed device. In measurement, the unloaded Q -factor of the fundamental TS mode is from several tens of thousands (the reference design) to only several hundred (the proposed design). Meanwhile, the unloaded Q -factor of the third overtone response for the proposed design could reach Q ∼95 000 with a decent Rm . The Q -factor ratio attains 170-180 between the third overtone and fundamental modes. With the feature of low Q -factor on the fundamental mode, the oscillator system could successfully oscillate at a higher frequency without the help of bandpass filtering. Finally, the closed-loop oscillation measurement is performed for the phase noise (PN) characterization. The PN performance could reach -154.5 dBc/Hz at a 1-kHz offset at the carrier frequency of ∼ 60 MHz. This technique has proven its potential as a future solution of high-frequency quartz oscillator technology.

Functionalized Copper Phthalocyanine and Zinc Phthalocyanine as a Coating Layer on the Sensitivity of QCM-Based VOCs Sensor

<p>The sensitivity of a QCM-based VOCs sensor with two kinds of a metal phthalocyanine, i.e., copper phthalocyanine (CuPc) and zinc phthalocyanine (ZnPc) was examined for various VOCs. The sensitivity of the two metal phthalocyanine was determined by the compatibility of the overlapped metal orbitals (Cu(II) dan Zn(II)) and the corresponding VOCs. The CuPc and the ZnPc layer were deposited on the quartz crystal oscillator by a vacuum evaporation method. The frequency shift and the sensitivity of the sensors with the two functional layers were tested using 5 VOCs: formaldehyde, propanol, ethanol, toluene, and ketone. The CuPc sensor showed the highest sensitivity to formaldehyde. On the other hand, the ZnPc was highly sensitive to ethanol.</p>

Frequency Source Design of Fast Locking Laser Range Radar

Given the bad ranging precision in continuous wave laser range radar systems because of the large jitter of the main oscillator frequency source, this paper introduces the fast locking method, which is based on Field Programmable Gate Array (FPGA) and modified mixed Charge Pump Phase Locked Loop (CPPLL), effectively improving the locking time of PLL frequency source. The input frequency is generated by a temperature compensation quartz crystal oscillator with high stability frequency (TCXO). It improves the PLL performance using the two-order active filter, reduces the phase detector dead-banding, and improves the frequency stability through the buffer insertion in PFD. The traditional PLL was improved by using preset voltage mode, which improves the PLL lock time. Finally, it analyzes the influence of frequency stability on the ranging accuracy of laser radar. The test results show that PLL lock time is up to 1.6ms. It can be applied to continuous wave laser radar ranging systems.

Development of Two-Stage Quartz-Crystal Oscillators Using Monolithic Four-Terminal CFOAs

In this article, based on the well-known circuits of two-stage quartz-crystal oscillators, three electronic circuits with a small number of external components are presented. For the proposed circuit configurations, the active elements are composed of monolithic current-feedback operational amplifiers (CFOAs) with access to terminal z, between the first stage (positive second-generation current conveyor (CCII)) and the second stage (output buffer). In this way, the output signal for the developed circuits is obtained after the output buffer of the second CFOA, thereby providing a minimal effect on the resonant circuit of the oscillators. Based on a theoretical analysis of the operational principle for the proposed circuits, the linear characteristic equations and the related self-oscillation conditions are obtained. Moreover, the frequency stability coefficients are determined, which can be obtained with larger values compared to the coefficients of the known discrete transistor circuits. To verify the operability and efficiency of the proposed oscillator circuits, experimental results obtained from sample electronic circuits are presented, which confirm the analyses performed in the frequency range up to about 10 MHz.

New Measurement Method of Viscosity, Density, and Dielectric Constant of Transformer Oil Based on Quartz Tuning Fork

Transformer oil is a liquid insulating material used in ultra-high voltage power equipment such as oil-immersed transformers and reactors. Online monitoring of its characteristics helps to maintain the status of power equipment. Aiming at the problem of single detection parameter in traditional methods, a new detection method for density, viscosity and dielectric constant based on quartz tuning fork is proposed in this paper. Firstly, by analyzing the working mechanism of the quartz tuning fork, the sensor detection model and parameter extraction method in air are constructed based on the equivalent circuit model of the Butterworth-Van Dyke model. Then, the working mechanism of the density, viscosity and dielectric constant of the transformer oil is analyzed, and the method of parameter extraction of sensor in standard oil sample and measurement model of sensor in oil sample to be measured are obtained. Finally, an experimental platform is built to verify the above conclusions. The results show that the quartz tuning fork detection model has good repeatability, the measurement errors of density, viscosity and dielectric constant are 2.52%, 6.53% and 3.36%, respectively, which meet the online monitoring accuracy requirements. The detection technology of transformer viscosity, density and dielectric constant based on quartz tuning fork realizes the simultaneous detection of three parameters in the same method, which meets the requirements of miniaturization, diversification and real-time detection of power parameters under the condition maintenance system, and also provides a new application scenario for tuning fork quartz crystal oscillators.

A Model for Sonochemistry in a Thin Layer Sonochemical Cell: What Constructive Interference Yields

Traditional sonochemistry (TS) in bulk solution is violent and expensive. Typically, a high power (> 60 W) ultrasonic horn is directed at a planar working electrode. Compression and rarefaction oscillations elicit cavitation bubble formation. Upon bubble collapse, high temperature (> 5000 K) and pressure (> 1000 atm) are produced locally, which enhances rates of chemical reactions. Bubble collapse near the electrode causes solvent jets directed at the surface to effect the surface cleaning and mass transport enhancements attributed to TS.While productive, TS obscures quantitative measurement of electron transfer kinetics and mass transport and requires a large laboratory footprint. An alternative and efficient sonochemistry is needed. Thin Layer Sonochemistry (TLS) exploits natural acoustics in a thin layer electrochemical cell. Low power transducers (e.g., quartz crystal oscillators) are appropriate because TLS achieves resonance in the cell to amplify input sound to the limit set by the solvent. TLS is more efficient and allows finer control of experimental and acoustic parameters. The footprint of TLS is minimal, and so TLS is appropriate for energy production applications (e.g., fuel cells) in portable devices.Experience suggests a subtle relationship between acoustic parameters and resonance. Here, a model is presented for calculation and explanation of resonance in a thin layer sonochemical cell. Background physics are explained and a step-by-step assembly guide is presented.

Anion Exchange and Water Dynamics in a Phosphonium-Based Alkaline Anion Exchange Membrane Material for Fuel Cells: An Electrochemical Quartz Crystal Microbalance Study.

The anion exchange and water dynamics of a phosphonium-based alkaline anion exchange membrane (AAEM) during the methanol oxidation process have been studied with the electrochemical quartz crystal microbalance (EQCM). The viscoelastic effects of the phosphonium-based AAEM in water and the optimal film thickness for EQCM analysis were identified by acoustic impedance analysis. The phosphonium-based AAEM exhibited stronger mechanical toughness in water when compared to a quaternary-ammonium-based membrane that was studied previously. From the simultaneous measurement of the electrochemical response and the frequency changes of the quartz crystal oscillator, water ingress/egress to/from the AAEM film was found to accompany the hydrogen adsorption/desorption, Pt oxidation process, and methanol oxidation process. The in situ study of AAEM films helps illustrate the critical role that water transport plays in electrochemical processes during the operation of anion exchange membrane fuel cells. The generated CO32- and HCOO-, during methanol oxidation, were absorbed into the AAEM film, replacing the OH- in the film, as shown by the decrease in frequency after one potential cycle. The exchange of OH- by CO32- and HCOO- was found to be reversible. These results provide insights into the anion exchange processes in membranes and emphasize the importance of characterizing the hydrated membranes under electrochemical conditions.

Joint Estimation of Phase Offset and Frequency Skew for Saving Energy in Wireless Sensor Networks

Due to the inherent instability of quartz crystal oscillators and difference in starting time, there are always phase offsets and frequency skews between sensor nodes in wireless sensor networks (WSNs). Time synchronization is a procedure to provide a common time notion across a WSN. Since a limited energy supply is the main constraint condition, energy-saving time synchronization design is a complex problem in WSNs. At present, time synchronization mainly relies on the statistical signal processing method. This increases the number of timing messages to improve the accuracy, which will lead to an energy overhead. In this paper, we introduce an effective energy-saving method to jointly estimate the phase offset and frequency skew. In testing, we identify boundary properties of the clock drift and analyze them in detail. Based on these properties, the proposed time synchronization method only requires two data samples and obtains a suitable estimator by using linear programming. Therefore, this approach attains a lower energy consumption than the conventional likelihood estimation method. In addition, it does not need to consider the probability distribution of the network delay and attains a notable robustness.

A chip-scale frequency down-conversion realized by MEMS-based filter and local oscillator

A wide-width clamped-clamped beam (CC-beam) resonator and a filter realized using mechanically-coupled resonator tanks have been extensively characterized to attain mixler (i.e., mixer-filter) functionality for a chip-scale frequency translation. Such a resonator has been driven into the nonlinear regime to explore its effect on the mixler operation as well as to obtain the best phase noise performance using the phase-feedback method. The proposed electrostatically transduced mixler operates by utilizing the local oscillator (LO) signal generated from the resonator itself, thus eliminating the need of a function generator or an external quartz crystal oscillator. This technique implemented with all the components on the same silicon substrate shows great potential for miniaturization in wireless communication while achieving 14.4 dB overall mixler loss.

(Invited) Thin Layer Sonoelectrochemistry: Impacts on Slow Electron Transfer Kinetics without Visible Cavitation

Sonochemistry and sonoelectrochemistry are typically undertaken in a bulk fluid with sonication of sufficient intensity to generate visible cavitation. Sonoelectrochemistry was undertaken in a thin layer of fluid with a quartz crystal oscillator. In the thin layer configuration, no cavitation is visible and mass transport is not impacted, but impacts on electron transfer kinetics are observed. Because there is no visible cavitation, cyclic voltammetric responses typical of a quiescent electrolyte are observed. From the voltammograms for species that undergo rapid heterogeneous electron transfer such as outer sphere Ru(bpy)₃²⁺⇌Ru(bpy)₃³⁺+e, voltammetric morphology is unchanged on sonication of a thin layer of fluid. For Fe³+e⇌ Fe² that undergoes quasireversible (slower) electron transfer under cyclic voltammetric perturbation, sonication in a thin layer is found to increase the rate of heterogeneous electron transfer by roughly an order of magnitude. Sonoelectrochemical catalysis for inherently slow heterogeneous electron transfer processes is generated and observed in a thin layer of electrolyte. In the experiments reported here, the fluid layer was less than the wavelength of sonication. The aqueous electrolyte contains redox species and acid. Experiments were undertaken at a platinum wire electrode using a 41 kHz quartz crystal oscillator. For the same experimental conditions, no impact on the electron transfer reversible Ru(bpy)₃²⁺ was observed. All data were collected at a fixed frequency; impacts varied with oscillator intensity. As with many sonoelectrochemical experiments, subtle variation in experimental parameters complicate generation of reproducible results. Here, data generated by two different experimentalists yield similar outcomes. Best operating conditions differed slightly for the two experimentalists but the pattern of increased interfacial electron transfer rates for iron on sonication was found by both. Reference [1] Johna Leddy, Chester G. Duda, Jacob Lyon, and William J. Leddy III, "Thin Layer Sonoelectrochemistry and Sonoelectrochemistry Devices and Methods," published 28 May 2015 as US Patent Application 20150147594 A1.

A fast phase tracking reference-less all-digital CDR circuit for human body channel communication

This paper presents a fast phase tracking and reference-less all-digital clock and data recovery circuit (ADCDR) for body channel communication (BCC) applications. The proposed ADCDR uses the novel phase-error calculation without a reference clock signal to improve the phase-tracking ability and reduce overall power consumption by eliminating the requirement for an external quartz crystal oscillator. In addition, the proposed gain-calibration method can automatically calibrate the gain value under different process-voltage-temperature (PVT) conditions to quickly compensate for the phase error. The wideband signaling (WBS) transceiver, including the proposed ADCDR is implemented using a 90-nm CMOS process with a core area of 0.36 mm2. The maximum transmission data rate of the proposed design is 20 Mb/s and power consumption is 2.2 mW, which are very suitable for the wearable device applications as compared with the traditional designs.

2P2-15 Applying the Internet of things and quartz crystal microbalance oscillators to quality factor measurement

2P2-15 Applying the Internet of things and quartz crystal microbalance oscillators to quality factor measurement

Оптимізація за швидкодією автопідстроювання частоти кварцового генератора системи автоматизованого контролю синхросигналів

Оптимізація за швидкодією автопідстроювання частоти кварцового генератора системи автоматизованого контролю синхросигналів

An on-chip fully electronic molecular clock based on sub-terahertz rotational spectroscopy

Mobile electronic devices require stable, portable and energy-efficient frequency references (or clocks). However, current approaches using quartz-crystal and microelectromechanical oscillators suffer from frequency drift. Recent advances in chip-scale atomic clocks, which probe the hyperfine transitions of evaporated alkali atoms, have led to devices that can overcome this issue, but their complex construction, cost and power consumption limit their broader deployment. Here we show that sub-terahertz rotational transitions of polar gaseous molecules can be used as frequency bases to create low-cost, low-power miniaturized clocks. We report two molecular clocks probing carbonyl sulfide (16O12C32S), which are based on laboratory-scale instruments and complementary metal–oxide–semiconductor chips. Compared with chip-scale atomic clocks, our approach is less sensitive to external influences and offers faster frequency error compensation, and, by eliminating the need for alkali metal evaporation, it offers faster start-up times and lower power consumption. Our work demonstrates the feasibility of monolithic integration of atomic-clock-grade frequency references in mainstream silicon-chip systems. The sub-terahertz rotational transitions of polar molecules can be used as frequency bases to create low-cost, low-power miniaturized clocks.