What Is a Crystal Oscillator?

Crystal oscillator refers to a piece of quartz (chip) is cut from a quartz crystal at a certain azimuth angle. A quartz crystal resonator is referred to as a quartz crystal or crystal, and a crystal oscillator [1]; and a crystal is added inside the package to form an oscillation circuit. The component is called a crystal oscillator. Its products are generally packaged in metal shells, but also in glass shells, ceramics or plastics.

1. General purpose crystal oscillator used in various circuits to generate

Total frequency difference: within the specified time, the maximum frequency difference between the crystal oscillator frequency and a given nominal frequency caused by all combinations of specified operating and non-operating parameters.

Note: The total frequency difference includes frequency temperature stability, frequency temperature accuracy, frequency aging rate, and frequency.

parameter

Basic description

Quartz crystal oscillator is a high-precision and high-stability oscillator. It is widely used in various types of oscillation circuits such as color TVs, computers, remote controls, and frequency generators in communication systems. It generates clock signals for data processing equipment and Provide a reference signal for a specific system ^[1]

The specific role of the crystal oscillator in the application, the clock source of the microcontroller can be divided into two categories: clock sources based on mechanical resonance devices, such as crystal,

1. Miniaturization, thinning and chipping: In order to meet the requirements of lightness, thinness, and shortness of portable products represented by mobile phones, the package of quartz crystal oscillators has been transformed from a traditional bare metal shell to plastic metal to ceramic packaging. Devices such as TCXO have shrunk by 30 to 100 times. The thickness of TCXO in SMD package is less than 2mm, and 5 × 3mm size devices are currently available.

2. High precision and high stability. The total accuracy of the uncompensated crystal oscillator can reach ± 25ppm. The frequency stability of VCXO can reach ± 20 100ppm in the range of 10 7 , while OCXO is in the same temperature range. Frequency stability is generally ± 0.0001 to 5ppm, and VCXO is controlled below ± 25ppm.

3, low noise, high frequency, frequency jitter is not allowed in GPS communication systems, phase noise is an important parameter to characterize the frequency jitter of the oscillator. The phase noise performance of OCXO mainstream products has been greatly improved. With the exception of VCXO, the maximum output frequency of other types of crystal oscillators does not exceed 200MHz. For example UCV4 series for GSM and other mobile phones

Quartz crystal oscillators are divided into non-temperature compensated crystal oscillators, temperature compensated crystal oscillators (TCXO), voltage controlled crystal oscillators (VCXO), thermostatically controlled crystal oscillators (OCXO), and digital / p compensated crystal oscillators ( DCXO / MCXO). Among them, the non-temperature-compensated crystal oscillator is the simplest one.

Crystal oscillators are widely used in military and civilian communication stations.

Title: Crystal Oscillator

Author: Zhao Sheng Heng

Publisher: Science Press

Publication time: May 2008

ISBN: 3

Folio: 16

Price: 62.00 yuan

Crystal oscillator content introduction

This book systematically explains the working principle and design method of low aging rate crystal oscillator, low noise crystal oscillator, voltage controlled crystal oscillator, integrated circuit crystal oscillator, temperature compensated crystal oscillator and MEMs oscillator. In order to help readers understand the various types of oscillator circuits in depth, the book describes the performance of resonators, electrical noise and low-noise electronic circuits, and the characterization of frequency stability in more detail.

This book can be used as a reference for engineering and technical personnel engaged in time and frequency control, and teachers and students of related majors in colleges and universities. reference book.