Crystal Oscillator Circuit Research Articles

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.

Design of New LED Curtain Wall Controller and Its Effect in Architectural Decoration

In recent years, LED with high brightness or ultra-high brightness has appeared. Because of its low production cost, it has been widely used. Compared with other display media, LED has the advantages of rich display content, wide dynamic range, vivid picture, no pollution, long life, etc., so it is used in building curtain wall facade decoration. This research designs LED curtain wall control system, the use of SD600 chip dimming control of LED, the use of absorbing current mode LED drive, further design of single SD600 chip application circuit, multi-SD600 chip application circuit. LED curtain wall display text need to design the corresponding graphic processing hardware, the hardware is composed of ARM microprocessor LPC2210 and its related peripheral circuits. The core chip of the LPC2210 processor chip needs 1.8 V working voltage, and the I/O interface voltage is 3.3 V, so it is necessary to design the corresponding power circuit; The system clock is adjusted through the internal PLL circuit to make the system run faster and design its crystal oscillator circuit; The power monitoring chip CAT1025JI-30 is adopted to build reset circuit, 20-pin interface type JTAG interface circuit; It is considered that the UARTO interface can’t be directly connected with the RS232 interface of PC, the MAX3232 chip is introduced for level conversion, and the serial interface circuit based on LPC2210 is designed. In the experiment, the new technology is used for outdoor lighting LED curtain wall construction, and the development tool uses the ADS1.2 provided by ARM company. The μC/OS-II embedded operating system is introduced to control the graphic processing hardware resources, reading the file from the SD card, and writing the text file and BMP file into the three-dimensional array, the corresponding text and pattern effect are displayed in the LED curtain wall.

Circuit Design of Counting Electronic Scale Based on STC89C51 Single Chip Microcomputer

The main purpose of electronic scales is to measure, which can also be said to be for trading. Electronic scales have their relevant numerical measurement value restrictions when they are used. Therefore, they can only be used effectively within the measurement value range when they are used. As long as the weight does not exceed the measurement limit, they can be used at will. This measurement method greatly improves the measurement speed and the user's trading speed. STC89C51 single chip microcomputer as an 8-bit single chip microcomputer, first of all, the price is relatively low. The number of pins of 51 single chip microcomputer is up to 40. After subtracting some power supplies and special pins, 32 pins can be used, and all 32 pins can be used as input and output pins. Therefore, the performance price ratio of 51 single chip microcomputer is relatively high. At the same time, the application circuit of 51 single chip microcomputer is relatively simple, and only the crystal oscillator circuit and reset circuit are needed to achieve work. Besides, 51 single chip microcomputer also has serial communication, timer, external interrupt and other on-chip resources, which can meet the special requirements of some systems. Finally, in terms of programming, the 51 single-chip microcomputer can be used only after loading the header file, without configuring the input and output ports, and is also very convenient in programming. Therefore, STC89C51 single chip microcomputer is used as the basis and Proteus and KILL software are used to realize the design of electronic scales.

Driver Circuit Design for a New Eddy Current Sensor in Displacement Measurement of Active Magnetic Bearing Systems

Position sensing is one of the crucial parts of the active magnetic bearing (AMB) system. The printed circuit board (PCB) eddy current position sensor is a new type of position sensor for the AMB system, which makes a compact structure, high sensing quality, and is low cost. In this article, an improved driver circuit is proposed for this new sensor. The driver circuit includes an excitation circuit and signal conditioning circuits. A crystal oscillator circuit with a power stage is used to provide the excitation coil with a stable excitation source of high stability and good precision of frequency. The analog demodulation circuit is designed for signal conditioning circuits to extract the rotor displacement information from the sensing coil outputs. Compared with the state-of-art driver schemes, the proposed method reduces the circuit complexity and cost. Accordingly, the experimental results show that the designed sensor has good linearity and sensitivity, and it can ensure AMB stable operation at the rated speed.

Design of Informatization College and University Teaching Management System Based on Improved Decision Tree Algorithm

At present, the teaching management system used in colleges cannot classify and store the teaching material information well and also has some problems, such as inaccurate calculation results of resource information weight, long response time, and large data query error. Therefore, this study designs an information college teaching management system based on improved decision tree algorithm. The hardware structure of the system consists of information communication structure, information teaching resource sharing structure, processor, and crystal oscillator circuit, and the core module is the data output control module. This study designs the system software based on the improved decision tree algorithm, creates a decision tree recursively, uses the CART decision tree to calculate the weight of teaching resource information, and constructs the fitness objective function of teaching resource information according to the mean clustering algorithm, so as to accurately extract the teaching resource information and realize the efficient processing of college teaching resource. The experimental results show that the response time of the system in this study is only 8 ms, the maximum convergence value is only 40, there is only one wrong data in the data query, and the storage time is 40 s. This system has a short response time, fast convergent rate, and a low probability of data search error when more than one client access the database at the same time.

Driver Circuit Improvement of Eddy Current Sensor in Displacement Measurement of High-Speed Rotor

Displacement sensor is the key component of the magnetic levitation system. Reducing complexity and improving reliability of the sensor circuits are very important to mass production of magnetic levitation devices. In this article, an improved driver circuit of eddy current sensor is proposed. In order to generate a stable oscillating source with high stability and good precision of frequency, a crystal oscillator circuit with power boost is used to replace the traditional Colpitts oscillator circuit. The improved modulation circuit is composed of passive components with a simple structure for improving reliability. The parameters design method of the modulation circuit is analyzed in detail, which greatly affects the sensitivity and linearity of the sensor. The experimental results show that the designed eddy current sensor has good linearity (1.12%) and sensitivity (2.14 V/mm), and it can ensure the stable operation of the magnetic levitated turbomolecular pump at the rated speed.

Ground Simulation Tests in Two-Dimensional Dynamic Acceleration Environment

Acceleration environment (AE) simulation tests have been widely applied in various areas such as aviation, space, environmental medicine, medical science, biomedicine, and materials. Most existing AE simulation test methods adopt impact and flight overload simulation separately, which cannot realize the synchronous controllable loading of two-dimensional (2-D) dynamic acceleration. In this paper, we propose and implement an AE simulation test method using an air-cannon-started compound centrifugal turntable. Specifically, our method emphasizes two processes, i.e., orderly transition from impact overload to steady-state overload and synchronous loading of 2-D dynamic AE. To further facilitate the method verification in AE, we develop a specialized simulation test platform. During field tests, axial acceleration of the unit being tested reached 20 g in 0.12 s at the launching stage and radial acceleration raised from zero g to 40 g in 0.5 s at the flight stage, achieving simulation of the 2-D dynamic AE. The obtained results show the effectiveness of the proposed simulation method, shedding light on updated design and control of impact simulation tests on the structures of crystal oscillator circuit, acceleration sensors, and related instruments.

Fast start crystal oscillator design with negative resistance control

Clock is an essential part of most of the integrated circuits as time base reference. It must be very accurate, highly reliable and readily available as soon as it is enabled. In all types of oscillator architectures, crystal oscillator is the most accurate and stable clock generator. But usually the crystal oscillator circuit suffers from slow startup. Therefore, it is essential to improve the startup time with optimally controlled crystal drive such that crystal drive power rating is not compromised. We propose a method that discusses about increasing the negative resistance during startup, using a startup circuit for fast start. Once the reliable startup is achieved, the negative resistance is decreased and the startup circuit is disconnected. The reduction in negative resistance is done with current steps and there are two ways in which it is achieved, the Digital control method and Analog control method. In digital control method, the current steps are timed at regular intervals and in analog control method, oscillator output amplitude is given as feedback to the startup circuit there by reducing the negative resistance. In the 32768 Hz real time clock generating oscillator, the startup time can be improved from 330 ms to 220 ms using the conventional startup method. With the proposed digital control method, lesser startup time of 160 ms is achieved and in analog control method it is further reduced to 120 ms.

SPICE simulation of tunnel FET aiming at 32 kHz crystal-oscillator operation

We numerically investigate the possibility of using Tunnel field-effect transistor (TFET) in a 32 kHz crystal oscillator circuit to reduce power consumption. A simulation using SPICE (Simulation Program with Integrated Circuit Emphasis) is carried out based on a conventional CMOS transistor model. It is shown that the power consumption of TFET is one-tenth that of conventional low-power CMOS.

Design, Modeling, and Experiment of a Piezoelectric Pressure Sensor Based on a Thickness-Shear-Mode Crystal Resonator

This paper presents the design, modeling, and experimental demonstration of a novel pressure sensor using an AT-cut quartz crystal resonator with beat frequency analysis-based temperature compensation technique. The combination of a compact design of the proposed pie-zoelectric crystal resonator structure and temperature compensation technique has advantages such as high accuracy, low cost, and good performance attributes. The sensor measures pressure and temperature simultaneously with a single AT-cut quartz resonator, thus avoiding the thermal lag problem in the commercial multiresonator-based pressure sensors. The pressure sensor is designed using computer-aided design software and CAE software (COMSOL Multiphysics). Finite-element analysis (FEA) of the pressure sensor is performed to analyze the stress–strain of the sensor's mechanical structure. A 3-D-printing prototype of the sensor was fabricated, and the sensing principle was verified using a force–frequency analysis apparatus. Subsequently, a full-up pressure sensor was fabricated with a stainless steel housing and a built-in crystal oscillator circuit. Based on the FEA and experimental results, we have determined that the maximum pressure the sensor can safely measure is 45 psi. Test results performed on the stainless steel product show a good linear relationship between the input (pressure) and the output (frequency).

A 1.5 nW, 32.768 kHz XTAL Oscillator Operational From a 0.3 V Supply

This paper presents an ultra-low power crystal (XTAL) oscillator circuit for generating a 32.768 kHz clock source for real-time clock generation. An inverting amplifier operational from 0.3 V $V_{DD}$ oscillates the XTAL resonator and achieves a power consumption of 2.1 nW. A duty-cycling technique powers down the XTAL amplifier without losing the oscillation and reduces the power consumption to 1.5 nW. The proposed circuit is implemented in 130 nm CMOS with an area of $0.0625 \text{mm}^{2}$ and achieves a temperature stability of 1.85 ppm/°C.

微量液体に対応した水晶発振回路式液体濃度センサの開発

In this paper, the liquid concentration sensor using crystal oscillator circuit which is available for measuring microdroplet is reported. We optimized the design of the sensing capacitor (SC) for sensing microdroplet. An electric-field-concentrated SC was used for measuring the liquid. The SC incorporated into the quartz oscillator has high-sensitivity because of the high stable crystal oscillator circuit. The SC is embedded in a silicone rubber. A spatially confined electric field is generated over the rubber. Therefore, the frequency of the oscillator changes by the contact with a liquid to the rubber. Moreover, the change less affected by a quantity of liquid. Because the frequency changes relate to the electrical characteristics of the liquid, the concentration of the liquid can be measured by the sensor. This sensor is expected to be applied to factory automation.

2A2-R03 人工皮膚下への埋め込みを想定した水晶発振回路式液体濃度センサの開発

In this paper, we report the development of liquid concentration sensor using crystal oscillator circuit embedded in a robotic artificial skin. We optimized the shape of the sensing capacitor for sensing a small quantity of liquid locally. This sensor is composed of the sensing capacitor and quartz crystal resonator (QCR). The frequency of QCR changes by a liquid in contact with the artificial skin on the sensing capacitor. Because the frequency changes relate to the electrical characteristics (dielectric constant, conductivity) of the liquid, the sensor can measure the concentration of the liquid. This sensor is expected to be applied to a sensor embedded in the robotic artificial skin.

Compatibility of the Active Inductance Double Resonance Quartz Oscillator with Q-MEMS Temperature Sensor

Low-frequency double-resonance quartz crystal oscillator circuit was developed with active inductance aiming the quick start-up in the intermittent operation on the sensor circuit and DC isolation using a Q-MEMS sensing crystal HTS-206. Allan standard deviation indicated 5 × 10–12, showing short range stability of the sensor circuit sufficient for the ubiquitous environmental sen sor network.

Design of a novel differential quadrature crystal oscillator

A novel crystal oscillator circuit with differential quadrature outputs is presented in this paper. It couples two differential Pierce structures with an annular cascade structure to realize differ...

The Design of Ward Calling System Based on SCM

This is a ward-called system of 64-bed. Its core component is an AT89C51 single-chip with rich internal storage resources. This system uses 8×8 matrix keyboard as its input device, a 2×8 LED as its static display, a 12MHz crystal oscillator circuit as its timer. A reset button is used to control its reset circuit. With the adoption of AT89C51 single-chip, the system has sufficient internal program memory unit and data storage unit. Therefore, there is no need for an external memory expansion with C programming language. For hospital, this is a low-cost, high-efficiency system with the advantages of easy-operation and convenient installation.

Study on the Design and the Stability of Integrated Quartz Resonator

By analysing the wafer, the electrodes, etc. according to the energy limit theory and the ANSYS finite element simulation, in this paper the author has designed the integrated quartz crystal resonator and oscillator circuit, and has carried on the experimental comparison on the stability of the integrated resonators, which have different structure, different electrode material and thickness. The experimental results show that the frequency stability of quartz crystal resonator is not only related with the electrode material and thickness, but also related with the structure. Under the same condition, resonator of asymmetric structure has better frequency stability, and the stability of Au-electrode was better than others, and its magnitude could reach 10 10. With the increase of the electrode thickness, the resonator oscillator stability will be improved.

Design of Intelligent Stepping Motor Control System

According to the applications of stepping motor in industrial controlling fields, an intelligent control system is designed based on personal computer and single chip machine in this paper. The working principle and control mode of stepping motor are introduced firstly. Then, the hardware of single chip machine system is introduced; especially the crystal oscillator circuit, driving circuit, power circuit, LED display circuit, watchdog circuit and serial communication circuit are analyzed in details. Finally the software including motor controlling program, communication program and human-machine interface program are designed. The practice showed that the system has the characters of good performance and low cost, so it can be widely used in stepping motor controlling.

Short‐term stability in the intermediate region between quartz crystal oscillation and LC oscillation

AbstractIn a quartz crystal oscillator circuit, an LC resonance circuit was inserted that enabled major enlargement of the variable range of frequency compared with the conventional Colpitts or Pierce quartz crystal oscillator. The short‐term stability of the oscillation was measured with Allan variance in the intermediate region between the quartz resonance and LC resonance, showing higher stability compared with the common LC oscillator. The analytical result is presented showing continuous transition from the quartz resonance to the LC resonance. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Suppression of overtone oscillation and low‐current operation using novel‐design scheme for quartz crystal oscillators

AbstractA novel design is proposed for a low‐frequency quartz crystal oscillator circuit. Negative resistance in a low‐frequency CMOS‐inverter quartz oscillator was reviewed for the fundamental mode at 32 kHz and the overtone oscillation at 200 kHz. Suppression of the overtone oscillation, appropriate gain, and drive current reduction are realized by adding only three circuit components. Experimental results and an estimate of the absolute value of the negative resistance are presented for the conventional Colpitts circuit and two types of the quartz crystal oscillator circuit. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.