Unlock instant, AI-driven research and patent intelligence for your innovation.

Automatic calibration device and method for clock frequency source

A clock frequency and automatic calibration technology, which is applied in the direction of automatic power control, power oscillators, electrical components, etc., can solve the problems of system clock frequency drift, affecting equipment communication performance, inconvenient use and maintenance, etc., and achieve high clock accuracy requirements , Guaranteed frequency calibration convergence time, reliable functional performance

Pending Publication Date: 2022-06-24
NANJING PANDA HANDA TECH
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Most of the communication devices use temperature-compensated crystal oscillator (TCXO) or constant temperature crystal oscillator (OCXO) as the system clock frequency source. Due to the long-term aging factors of this type of crystal oscillator, the annual aging rate is generally around 1-2ppm, making The frequency drift of the system clock affects the communication performance of the device, and may cause communication failure in serious cases
[0003] For the system clock frequency drift caused by crystal oscillator aging, the common method is to regularly remove the device from the installation platform for inspection and maintenance, and it is necessary to open the device, connect the output of the crystal oscillator to a high-precision frequency counter instrument, and adjust the internal of the crystal oscillator mechanically. The potentiometer is used to calibrate the frequency source, which brings great inconvenience to users in use and maintenance

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Automatic calibration device and method for clock frequency source
  • Automatic calibration device and method for clock frequency source
  • Automatic calibration device and method for clock frequency source

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0074] The content of this embodiment mainly includes the design of the frequency source calibration circuit and the FPGA frequency calibration algorithm.

[0075] 1) Frequency source calibration circuit design

[0076] combine figure 1 , The frequency source calibration circuit is mainly composed of constant temperature crystal oscillator, FPGA, 16-bit high-precision DAC, active filter and auxiliary circuit. The nominal frequency of the constant temperature crystal oscillator used is 102.4MHz, the frequency stability is 0.1ppm, the annual aging is not more than 1ppm, the voltage control voltage range is 0.5~4.5V, the frequency adjustable range is greater than ±2ppm, and the voltage control linearity is not greater than ±2ppm. 10%; DAC adopts 16bit low-power integrated circuit with on-chip 2.5V, 5ppm / ℃ reference voltage, controlled by SPI serial interface; active filter is composed of low-noise, low-drift op amp and RC circuit. Pass the filter to suppress interference, reduc...

Embodiment approach

[0098] combine Figure 4 , the high-precision automatic calibration frequency source implementation method:

[0099] ① Power on the equipment and the Beidou module using the invention respectively, and preheat for 10 minutes, so that the equipment and the Beidou module can work stably;

[0100] ②Connect the output frequency of the constant temperature crystal oscillator to the high-precision frequency counter, use the test terminal to manually preset the voltage-controlled voltage value output by the internal DAC of the device through the serial port, until the frequency error measured by the high-precision frequency counter reaches 1ppb, record the frequency value and the voltage-controlled voltage value voltage value;

[0101] ③ Manually preset the value of the voltage-controlled voltage output by the internal DAC of the device through the serial port of the test terminal, until the frequency error measured by the high-precision frequency counter reaches +1ppm and +2ppm, an...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses an automatic calibration device and method for a clock frequency source. The device comprises a constant temperature crystal oscillator, an FPGA unit, a DAC unit, an active filter and an auxiliary circuit. The method comprises the steps that the frequency output of the constant temperature crystal oscillator serves as a working clock of the FPGA unit; the FPGA unit performs internal clock counting and calibration according to pulse per second of an external Beidou module, and then controls the DAC unit to output analog voltage through an SPI serial interface; the analog voltage is driven by an active filter, interference filtering is suppressed, voltage-controlled voltage is output and acts on a voltage-controlled adjusting end of the oven controlled crystal oscillator, and the output frequency of the oven controlled crystal oscillator is adjusted in real time. By comparing the accessed external high-precision pulse per second with the clock generated by the internal frequency source, the internal clock frequency is adjusted in a closed-loop manner, so that the frequency precision of the external high-precision pulse per second and the frequency precision of the internal frequency source are gradually close to each other, and the high-precision and automatic clock frequency source automatic calibration of the communication equipment is realized.

Description

technical field [0001] The invention relates to the technical field of clock frequency sources, in particular to an automatic calibration device and method of a clock frequency source. Background technique [0002] Most communication equipment uses temperature compensated crystal oscillator (TCXO) or oven controlled crystal oscillator (OCXO) as the system clock frequency source. The frequency of the system clock drifts, which affects the communication performance of the device, and may cause communication failure in severe cases. [0003] For the system clock frequency drift caused by the aging of the crystal oscillator, the common method is to periodically remove the equipment from the installation platform for inspection and maintenance, and the equipment needs to be opened, and the output of the crystal oscillator is connected to an external high-precision frequency counter instrument. The potentiometer is used to calibrate the frequency source, which brings great inconv...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H03L7/00H03B5/32
CPCH03L7/00H03B5/32
Inventor 张威刘林
Owner NANJING PANDA HANDA TECH