Clock Synchronization Circuit With Drift Compensation Lookup Table

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Solution Overview

Problem

Existing clock synchronization methods in distributed network systems face challenges in achieving high precision and consistency due to factors like crystal oscillator drift caused by temperature and aging, which affect the frequency of local clocks and impact the accuracy of time synchronization.

Innovation Solution

A time synchronization device comprising a signal generating circuit and a time adjusting circuit, where the signal generating circuit includes a control circuit to generate a frequency control word based on influence parameters such as temperature and aging, and a signal adjusting circuit to produce an output signal with a target frequency, which is used to synchronize the clock signal of an electronic apparatus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional clock synchronization methods are used, then the system is simple to implement, but the time synchronization precision deteriorates due to crystal oscillator drift

Engineering Contradiction:
Improvetime synchronization precisionVSAvoidsynchronization device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing compensation values for crystal oscillator drift in a lookup table before actual operation. The temperature-compensated crystal oscillator characteristics are characterized in advance, and compensation data is prepared beforehand based on temperature ranges and aging periods. During runtime, the system only needs to query the pre-computed table and apply the corresponding compensation, avoiding complex real-time calculations while achieving high precision frequency compensation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism by inserting a compensation circuit between the crystal oscillator and the phase-locked loop. This intermediary circuit includes a lookup table storing pre-computed compensation values, a temperature sensor to detect operating conditions, and a frequency adjustment mechanism. The intermediary translates the raw oscillator signal into a compensated signal by selecting appropriate correction values from the lookup table based on temperature and aging parameters, thereby eliminating drift without requiring complex real-time processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If frequency compensation for temperature and aging is implemented, then the time synchronization precision is improved, but the device complexity increases

Engineering Contradiction:
Improvefrequency measurement precisionVSAvoidcompensation circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs a cost-effective approach by using a simple lookup table implemented in ROM or RAM rather than complex analog compensation circuits. The compensation data is stored as discrete values that can be easily updated or replaced. The system uses basic digital logic to query and apply compensation values, avoiding expensive precision analog components. This disposable-style approach allows the compensation mechanism to be implemented with inexpensive digital components while achieving high precision frequency stabilization.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent applies parameter changes by systematically varying the frequency compensation parameters based on temperature and aging conditions. The lookup table is organized with temperature ranges as primary indices and aging periods as secondary indices, allowing the system to select appropriate compensation values by changing these parameters. The compensation amount is adjusted in discrete steps corresponding to different temperature intervals and aging milestones, transforming a continuous compensation problem into a manageable discrete parameter selection process.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3806355B1Time synchronization device, electronic device, time synchronization system and time synchronization method
Publication Date: 2025.02.12 BOE TECHNOLOGY GROUP CO LTD
  • EP3806355B1 patent drawingFigure 1~3
  • EP3806355B1 patent drawingFigure 4~6A
  • EP3806355B1 patent drawingFigure 6B~7

AI summary

Disclosed are a time synchronization device (1000) for an electronic device, an electronic device (50), a time synchronization system (60) and a time synchronization method. The time synchronization device (1000) comprises: a signal generation circuit (100) and a time adjustment circuit (150). The signal generation circuit (100) includes: a control circuit (11) configured to generate a frequency control word (F); and a signal conditioning circuit (12) configured to receive an input signal having an original frequency and the frequency control word (F), and to generate and output, according to the frequency control word (F) and the input signal, an output signal having a target frequency. The time adjustment circuit (150) is configured to perform synchronization regulation on a clock signal of the electronic device on the basis of the output signal having the target frequency. The time synchronization device (1000) can synthesize, by means of the signal generation circuit (100), an output signal having a sufficiently large frequency; a frequency granularity of the output signal is high, so that the electronic device obtains a more precise synchronous clock, and the working coordination and consistency of the electronic device in a network system is better.