Portable Unit Clock Calibration Using Phase Drift Feedback

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Solution Overview

Problem

Existing electronic devices, such as wireless phones, require costly manufacturing processes and field recalibration due to clock drift issues, necessitating initial calibration and additional hardware, which is inefficient and costly.

Innovation Solution

Implementing an automatic field calibration method that synchronizes the clock of a portable unit with a fixed unit using a dummy carrier and adjusting the clock frequency to maintain synchronization within a predetermined range, eliminating the need for initial calibration during manufacturing and reducing hardware requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If calibration is performed in manufacturing, then initial clock synchronization is achieved, but manufacturing cost increases due to additional testing time and hardware requirements

Engineering Contradiction:

Improveclock calibration accuracyVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The system performs preliminary calibration actions during manufacturing by embedding calibration data in the binary file, but the actual clock synchronization is finalized automatically in the field when the portable unit connects to the fixed unit, eliminating the need for extensive manufacturing testing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The portable unit automatically performs its own clock calibration in the field by receiving calibration data from the fixed unit through wireless communication, eliminating the need for external manufacturing testing equipment and reducing manufacturing costs

Inventive Principle:

Principle #25Self-service

2Reliability

If field recalibration is performed, then clock synchronization is restored, but operational disruption occurs during calibration

Engineering Contradiction:

Improveclock synchronizationVSAvoidoperational continuity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs periodic automatic calibration at predetermined intervals when the portable unit connects to the fixed unit, maintaining clock synchronization without requiring manual intervention or causing operational disruption

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The system continuously monitors clock drift between the portable and fixed units, and automatically triggers calibration when drift exceeds predetermined thresholds, maintaining synchronization without operational interruption

Inventive Principle:

Principle #23Feedback

3Stability of the object's composition

If accurate crystals are used in portable unit, then clock stability is improved, but manufacturing cost increases

Engineering Contradiction:

Improveclock stabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Instead of relying on expensive accurate crystals, the system changes the approach by using software-based clock drift compensation and automatic calibration, adjusting clock parameters dynamically to maintain stability without requiring expensive hardware

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system replaces expensive accurate crystals with standard, less expensive crystal oscillators, compensating for the reduced hardware accuracy through automatic calibration and drift compensation algorithms

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Measurement precision

If additional calibration hardware is added, then calibration precision is improved, but device complexity increases

Engineering Contradiction:

Improvecalibration precisionVSAvoidhardware complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The fixed unit serves multiple functions: it acts as both a data storage device and a calibration reference source. The calibration data is embedded in the binary file that is already transmitted to the portable unit, eliminating the need for separate calibration hardware

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The binary file serves as an intermediary carrier that transports calibration data from the fixed unit to the portable unit through existing wireless communication channels, eliminating the need for dedicated calibration hardware interfaces

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS9673971B2Automatic clock calibration of a remote unit using phase drift

Publication Date: 2017.06.06 DIALOG SEMICONDUCTOR BV

AI summary

An automatic calibration of a clock of a wireless portable part with respect to a clock of a fixed part in a field environment. The calibration performed in the field environment negates the need to calibrate the clock during manufacture and negates the need for an initial field recalibration because of temperature differences between manufacture and the field. In performing the calibration the frequency of the clock of the portable part is varied until the portable part is synchronous with the fixed part to with in a range of timing bits. The portable part is declared calibrated after remaining calibrated for a defined number of data frames.