Master Timer Derivation Using High-Resolution Timer for Wireless Sync

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Solution Overview

Problem

Conventional clock synchronization methods in wireless communication systems require real-time transmission of accurate master timer information, which can be error-prone due to delays and uncertainties, especially when the master timer is external to the wireless module, leading to synchronization inaccuracies.

Innovation Solution

A method that derives a master timer with acceptable accuracy from a coarse timer interrupt and a high-resolution timer, allowing synchronization of electronic devices without the need for real-time transmission of master timer information, even when the coarse timer interrupt has a much larger granularity than the precision required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If real-time transmission of master timer information is used for synchronization, then synchronization can be achieved, but synchronization accuracy deteriorates due to delays and uncertainties

Engineering Contradiction:

Improvesynchronization reliabilityVSAvoidsynchronization accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system pre-calculates and stores the relationship between the coarse timer interrupt and the system master timer in advance. When synchronization is needed, the pre-computed relationship is used to derive the master timer value without requiring real-time transmission, thus avoiding delays and maintaining high accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A high-resolution timer is introduced as an intermediary between the coarse timer interrupt and the system master timer. The high-resolution timer provides fine-grained timing measurements that bridge the gap between the low-resolution interrupt and the required master timer precision, enabling accurate synchronization without real-time master timer transmission.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a high-resolution timer is used to improve timing precision, then measurement precision improves, but device complexity increases

Engineering Contradiction:

Improvetiming precisionVSAvoidtimer system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The high-resolution timer is designed to serve multiple functions: it acts as both a precise timing reference for deriving the master timer and a synchronization reference for the wireless module. This multi-functionality reduces the need for separate dedicated timing circuits, thereby limiting the increase in device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The timer system is structured in nested layers: the coarse timer interrupt provides the outer time framework, the high-resolution timer provides the inner precise measurements, and together they derive the system master timer. This nested structure allows each timer to operate at its optimal resolution level while contributing to the overall synchronization system.

Inventive Principle:

Principle #7Nested doll (Nesting)

3Adaptability or versatility

If the master timer is external to the wireless module, then system modularity improves, but synchronization reliability deteriorates due to delays and uncertainties

Engineering Contradiction:

Improvesystem modularityVSAvoidsynchronization reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system implements a feedback mechanism where the derived master timer value is continuously compared with the actual system time, and correction factors are applied to maintain synchronization accuracy. This feedback loop compensates for delays and uncertainties introduced by the external master timer location, preserving synchronization reliability while maintaining modularity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces the direct mechanical/clock signal connection between the master timer and wireless module with a software-based time derivation and correction system. This substitution allows the master timer to remain external and modular while using computational methods to maintain synchronization accuracy, overcoming the limitations of direct physical coupling.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8724615B1Method and apparatus for generation of a system master timebase of a computing device using indirect signalling of timing information

Publication Date: 2014.05.13 ATMEL CORP

AI summary

In a communication system comprising one master device and one or more slave devices, the slave devices synchronize to a common timebase maintained at the master device, independently of a wireless module timebase, without requiring transmission of accurate and real time master timer information from the master device. In one approach, a slave device sends timing information to the master device, the timing information representing the slave device timebase, and the master device sends back correction information to the slave device, the correction information representing a difference between the slave device timebase and the master device timebase, the correction information being usable independent of the timing of sending back the correction information. The master timebase might be a system master timer of an accurate timer based on a timer interrupt and a high resolution timer having a resolution greater than a timer interrupt resolution.