catalogue

1. What is a resonator and how does it work
  What is a resonator?
  How does a resonator work?
  What are the types of resonators?
2. Main technical parameters of resonator
3. Application field of resonator
4. Common problems and solutions
  What is the cause of frequency drift and how to solve it?
  How do I handle startup or vibration problems?
  What are the possible failures of the resonator?
5. Which is better for your application, quartz resonator or ceramic resonator?
6. Conclusion

Resonator, this component may be both familiar and unfamiliar to many people. It plays a vital role in the design of modern electronics, communications and precision instruments. Imagine that without resonators, the accurate transmission of wireless signals would be difficult, and various digital devices would not have a stable and reliable clock source. But understanding how resonators work and how to properly select and use them can often be a headache. The wrong choice will not only reduce the performance of the system, but also affect the overall reliability and stability.

Today, I'd like to talk to you about resonators. I'll start with the basic concepts and go through the different types, how they work, and the key technical parameters. At the same time, I will also share some practical application examples to give you a more intuitive understanding of how the resonator plays a role in different scenarios. In addition, I will give some practical suggestions and solutions to the problems you often encounter.

I hope that through this exchange, both friends who have just come into contact with this field and experienced professionals can have a clearer understanding of the resonator. In this way, when facing specific projects, you can be more confident to choose the right resonator, and can better cope with the various challenges that may arise. So, let's enter this wonderful world of resonators together!

1. What is a resonator and how does it work

What is a resonator?

A resonator is a device that can naturally vibrate or oscillate at a specific frequency. Such devices can be mechanical, electronic, or optical, and they are typically used to amplify signals in one frequency range while suppressing signals at other frequencies. Resonators are used in many fields, including radio communications, timing, filter design, and various scientific instruments.

How does a resonator work?

The operating principle of a resonator is based on natural frequencies or resonance phenomena in a physical system. When a system is subjected to an external excitation, such as a mechanical force, electrical signal, or light, if the frequency of the excitation matches the natural frequency of the system, the system will vibrate or oscillate at a greater amplitude, a process called resonance. In a mechanical resonator, such as a system consisting of a mass block and a spring, once excited, the mass block moves back and forth at a specific natural frequency under the action of an elastic force. This type of resonator is widely used in various sensors and Musical Instruments, such as tuning forks, which produce clear tones through their specific natural frequencies.

For electronic resonators, the most common form is the LC circuit, which consists of an inductor (L) and a capacitor (C). In this circuit, energy is alternated between an electric field (stored in a capacitor) and a magnetic field (stored in an inductor) at a specific resonant frequencyProceed. Crystal oscillators use quartz crystals as high-Q resonant elements to provide an extremely stable reference frequency for digital devices. These electronic resonators are critical in areas such as radio communications, timing devices, and precision instruments because they provide accurate and stable frequency signals.

Optical resonators form a standing wave pattern based on multiple reflections of light waves between two mirrors. When the frequency of the incident light matches the frequency of a mode supported by the cavity, the light energy is reflected repeatedly in the cavity without significant loss of energy, resulting in a strong resonance effect. A typical example is a laser, which contains an optical resonator that enables light to be amplified in the gain medium within the cavity and eventually partially output to form a laser beam. This kind of resonator is not only used in laser technology, but also has important applications in scientific research such as precision measurement and spectral analysis. In general, regardless of the type of resonator, they are designed to enhance the signal in a specific frequency range while suppressing interference from other non-resonant frequencies.

What are the types of resonators?

Resonators can be divided into many types according to different classification standards, the following are some common classification methods and their corresponding resonator types:

Mechanical resonators: This type of resonator uses mechanical vibrations to operate, such as:

• Spring - mass system

• Tuning fork

• Microelectromechanical systems (MEMS) resonators

Electronic resonator: A resonator operating on electrical principles, such as:

• LC resonant circuit: A circuit composed of inductors (L) and capacitors (C).

• Quartz crystal resonators (crystal oscillators) : Use the piezoelectric effect of quartz crystals.

• Ceramic resonators: Made of ceramic materials, the cost is lower, but the frequency accuracy is not as good as quartz crystals.

• Surface acoustic wave (SAW) resonators: Resonance is achieved by sound wave propagation on a piezoelectric substrate.

• Bulk acoustic wave (BAW) resonators: Similar to SAW, but propagate sound waves in the direction of thickness.

Optical resonators: These resonators involve the resonance of light waves, such as:

• Fabry-perot cavity: optical resonator consisting of two partial mirrors.

• Microring resonators: small resonant structures used in integrated optics.

• Fiber Bragg grating: a resonant structure formed by periodically varying refractive index in an optical fiber.

In-line (with leads) : This type of resonator usually has one or more pins that can be inserted directly into the holes in the printed circuit board. For example, some quartz crystals and ceramic resonators are in line.

Chip type (leadless) : Also known as surface mount technology (SMT), this type of resonator does not have a traditional pin, but is welded directly to the board surface. This form of resonator is widely used in modern electronic products.

2. Main technical parameters of resonator

Understanding the main parameters of the resonator helps engineers to design or select the appropriate resonator according to the specific application requirements.

Resonant frequency (f0) :

The resonant frequency is the frequency at which the resonator naturally vibrates or oscillates. It is the natural frequency that the system exhibits when it vibrates freely without external excitation. For electronic resonators such as LC circuits, this frequency can be formulatedIt is calculated; For mechanical resonators, it depends on the mass and elastic coefficient of the system.

Quality Factor (Q) :

The quality factor is an important index to measure the energy loss of the resonator, which represents the ratio of the resonant peak value of the resonator to the width of the surrounding frequency band. The higher the Q value, the better the selectivity of the resonator, that is, the stronger the ability to suppress the signal of the non-resonant frequency, and it means that the energy loss is lower and the oscillation can be maintained for a longer time. High Q values are important for applications that require precise frequency control.

Temperature coefficient (TCF) :

The temperature coefficient describes how the resonant frequency varies with temperature. Resonators made of different materials have different TCF, which means that changes in temperature will affect the operating frequency of the resonator. In precision timing and other applications requiring a high degree of stability, low TCF is very important.

Phase noise:

Phase noise refers to random fluctuations in the phase of the output signal relative to the ideal signal. This is one of the important parameters for evaluating resonators especially for high frequency reference sources such as crystal oscillators. Good phase noise characteristics mean a more stable frequency output.

Load Capacitance (CL) :

For quartz crystal resonators, load capacitance is a key parameter, which affects the actual operating frequency of the resonator. Load capacitors include stray capacitors in the external circuit and parasitic capacitors in the resonator itself package.

Drive level:

The drive level refers to the input power required in order for the resonator to achieve a specific amplitude of oscillation. Too high a drive level may cause nonlinear behavior of the resonator, which affects frequency stability and increases phase noise.

Aging rate:

The aging rate describes the frequency shift of the resonator over time. Some materials (such as quartz) have good long-term stability, but even high-quality resonators will undergo some degree of aging.

3. Application field of resonator

Resonators are likely to be used in any application that requires a stable frequency reference, signal filtering, or energy storage and release. For example:

Mobile phone: The crystal oscillator is used to provide a stable clock signal to ensure the accuracy and reliability of wireless communication.

Radio transceivers: Radio equipment, both civilian and military, requires high-precision resonators to ensure tuning to the correct frequency.

Wi-Fi routers and other network devices: In order to maintain the synchronization of data transmission, these devices often contain quartz crystals or other types of resonators.

Personal Computer (PC) : The crystal oscillator on the motherboard provides the clock signal for the CPU and other components.

Laptops and tablets: Also use crystal oscillators to maintain internal timing consistency.

Servers: Servers in the data center rely on a highly stable clock source to ensure the speed and accuracy of data processing.

Television: A stable clock for generating video and audio signals.

Sound systems: In digital audio processing, high-quality oscillators can improve sound quality.

Game console: Provides a benchmark clock for the processor to ensure smooth running of graphics rendering and game logic operations.

Navigation system: An oscillator in the GPS module helps to receive satellite signals and position them.

Entertainment systems: including car stereos, DVD players, etc., all rely on a stable clock signal.

Safety systems such as tire pressure monitoring systems (TPMS), which use wireless communication technology, also require precise frequency control.

Heart rate monitors: Some portable medical devices use resonators to generate or process physiological signals.

Ultrasonic imaging equipment: The use of high-frequency oscillators to produce ultrasonic signals.

Watches: Quartz watches use quartz crystals as a time reference.

Alarm clocks and wall-mounted clocks: Modern electronic clocks often also use crystal oscillators to keep time accurate.

Accelerometers: Some MEMS (micro-electro-mechanical System) accelerometers operate on the principle of mechanical resonance.

Pressure sensor: The resonant element is sensitive to pressure changes to measure pressure.

Spectrum analyzer: A high-precision local oscillator is required for frequency scanning.

Signal generator: Used to generate test signals of different frequencies.

Lasers: Optical resonators are a key part of lasers and are used to enhance specific wavelengths of light.

Particle accelerators: require very precise time synchronization and frequency control.

4. Common problems and solutions

What is the cause of frequency drift and how to solve it?

Frequency drift is one of the common problems of resonators. It refers to the phenomenon that the output frequency deviates from its nominal value over time or with the change of environmental conditions. This phenomenon may be caused by many factors, among which temperature change is one of the most important reasons. The physical properties of the material, such as capacitors and inductors, change with temperature, resulting in a shift in the resonant frequency. In addition, aging is also an important factor, and over time, crystals or other components may experience changes in their microstructure, which in turn causes a gradual shift in frequency. Power supply voltage fluctuations can also affect active resonators, such as crystal oscillators, because changes in voltage can affect the operating state of the internal amplifier, which in turn affects the output frequency. Mechanical stress or vibration, electromagnetic interference (EMI), and load effects introduced by external circuits are also common causes of frequency drift.

To address frequency drift due to temperature changes, components with low temperature coefficients, such as AT, can be used to cut quartz crystals and use temperature compensated circuits (TCXOs) or, in extreme cases, thermostatically controlled crystal oscillators (OCXOs). For problems caused by aging, select high-quality components that have been tested for a long time, and reserve adjustment allowances at the time of design in order to compensate for long-term aging effects through fine tuning. For power supply voltage fluctuations, you can use a regulated power supply or add additional power filters, and add a voltage regulation mechanism to the circuit to ensure that the oscillator always operates within the optimal voltage range.

In order to cope with the effects of mechanical stress or vibration, unnecessary pressure on the resonator should be avoided during installation, and shock absorbing materials or isolation devices should be used to reduce the impact of external vibrations. Reasonable wiring and shielding measures can help reduce the impact of electromagnetic interference on the resonator. For component parameter changes and load effects, select components with high accuracy and low drift rate, and match the load capacitance by accurate calculation, while providing adjustable circuit configurations to allow users to fine-tune according to the actual situation. Through these comprehensive measures, the problem of frequency drift can be effectively reduced or eliminated, and the reliability and stability of the system can be improved.

How do I handle startup or vibration problems?

When dealing with the starting problem of the resonator, it is first necessary to check whether the design of the feedback path is appropriate to ensure that it can provide the correct phase offset and sufficient gain to maintain the oscillation. If the circuit fails to start, the simulation tool can be used to analyze and adjust the feedback resistance, capacitance and other component values as needed. At the same time, a stable power supply is also key, and a stabilized power supply or filter should be used to reduce voltage fluctuations. For aging or damaged components, regular inspection and timely replacement are necessary. In addition, in temperature-sensitive applications, consider using temperature compensated oscillators (TCXOs) or thermostatically controlled oscillators (OCXOs) to reduce the impact of temperature changes on frequency.

For vibration problems, the impact of external vibration on the resonator can be mitigated by physical isolation, such as the use of elastic materials such as rubber pads or silicone to isolate the resonator from the mechanical structure. During the installation process, ensure that the resonator is firmly and correctly fixed on the PCB, and avoid too tight or too loose installation to reduce mechanical stress. For applications that must operate in high vibration environments, it is a good idea to choose a resonator product specifically designed for vibration resistance. In addition, strengthening the overall structural design of the equipment, such as the use of stronger housing materials and the addition of internal support structures, can improve seismic performance. Finally, the reliability of the equipment under expected conditions is verified through adequate vibration testing, and necessary adjustments are made according to the test results. These measures help to ensure the stable operation of the resonator under various environmental conditions.

What are the possible failures of the resonator?

Resonators may encounter a variety of faults during use, which may affect their performance and even cause the whole system to fail to work normally. Here are some common resonator failures and their causes:

Quality factor (Q value) decline:

Causes: aging of inductive or capacitive components, poor contact, increased parasitic resistance, electromagnetic interference in the environment, etc.

Effect: The decrease of Q value will make the selectivity of the resonator worse, the bandwidth will be widened, and the inhibition ability of the non-resonant frequency will be weakened.

Phase noise increase:

Causes: power supply noise, component parameter changes, external electromagnetic interference, etc.

Impact: Increased phase noise can lead to reduced signal quality, especially in high-precision applications such as wireless communications and precision measuring instruments.

Physical damage:

Causes: drop, impact, overheating, electrostatic discharge (ESD), etc.

Impact: Physical damage may cause the resonator to fail completely, requiring a new one.

Temperature coefficient deviation:

Reasons: Material properties change with temperature, or defects in the manufacturing process.

Influence: The deviation of the temperature coefficient will cause the performance of the resonator to be unstable at different temperatures, affecting the long-term stability.

Load effect:

The reason: The external circuit connected to the resonator may introduce additional capacitors or inductors, thus changing the actual operating frequency of the resonator.

Impact: This load effect can significantly change the operating point of the resonator, especially for quartz crystal resonators, which is particularly important.

Aging:

The reason: The material changes slightly over time, causing the frequency to slowly shift.

Impact: Although this is a gradual process, it can accumulate into significant frequency deviations over a long period of time.

In order to prevent these failures, appropriate measures can be taken at the design stage, such as selecting high-quality components, optimizing circuit layout, providing good heat dissipation conditions, conducting adequate test verification, and adopting protective measures to prevent electrostatic discharge and mechanical damage. In addition, regular maintenance and monitoring is also the key to ensure the long-term stability of the resonator.

5. Which is better for your application, quartz resonator or ceramic resonator?

Choosing a quartz or ceramic resonator depends on the needs of the specific application. Both have advantages and disadvantages and are suitable for different scenarios.

INFINITECH has summarized some of their pros and cons to help you decide which one is better for your application.

Quartz resonator

Advantages:

• High accuracy and stability: Quartz resonators provide very high frequency stability and temperature stability, especially for AT-cut quartz crystals, which perform well over a wide temperature range.

• Low aging rate: the aging rate of quartz materials is low, and the frequency drift is small after long-term use.

• Low phase noise: Quartz resonators generally have low phase noise and are suitable for applications that require high signal quality.

Cons:

• Higher cost: Compared to ceramic resonators, the cost of quartz resonators is usually higher.

• Larger volume: Quartz resonators may take up more space than ceramic resonators, especially in miniaturized designs.

• Longer start-up time: In some applications, quartz resonators may take longer to reach a stable operating state.

Ceramic resonator

Advantages:

• Low cost: The price of ceramic resonators is relatively low, suitable for mass production and cost-sensitive applications.

• Miniaturization: Ceramic resonators can be made very small, suitable for compact or portable devices.

• Fast start: Ceramic resonators usually have a fast start time, which is good for some applications with immediate response.

Cons:

• Poor frequency stability: compared with quartz resonators, ceramic resonators have a higher temperature coefficient, and the frequency varies more with temperature.

• Higher aging rate: The aging rate of ceramic resonators is higher than that of quartz resonators, and greater frequency offset may occur after a long time of use.

• Higher phase noise: The phase noise of ceramic resonators is usually higher than that of quartz resonators, which is not suitable for applications with strict signal quality requirements.

Application suggestion

• For applications with high accuracy, low phase noise, and long-term stability (such as communications equipment, precision instruments, timing devices, etc.), quartz resonators are a better choice.

• For applications that are cost-sensitive, require high miniaturization, and require less stringent frequency stability (such as consumer electronics, toys, household appliances, etc.), ceramic resonators may be a more suitable choice.

Other factors should also be considered before making a final decision, such as the power supply voltage range, operating environmental conditions (such as temperature, humidity), electromagnetic compatibility (EMC) requirements, etc. A comprehensive evaluation of these factors will help you choose the best type of resonator for your particular application. If possible, it is also a good way to perform actual tests to verify that the selected resonator meets all performance requirements.

6. Conclusion

Well, with today's discussion, we've explored all aspects of resonators together. From their basic concepts to different types of working principles, to those key technical parameters, and various cases in practical applications, I hope that these contents can help you to have a more comprehensive and in-depth understanding of the resonator.