Multimedia Clock Synchronization via Power Line Carrier

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Solution Overview

Problem

Existing methods for synchronizing clocks of multimedia stream restitution systems, such as loudspeakers, are not precise enough, with synchronization deviations greater than 5 milliseconds, which is inadequate for ensuring synchronized audio reproduction across multiple systems.

Innovation Solution

A method that utilizes the domestic electrical network to synchronize clocks of multimedia stream restitution systems by detecting pulses and generating a high-frequency clock signal, allowing for precise synchronization with a deviation of less than 100 microseconds, enabling synchronized multimedia stream restitution across systems without physical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If Network Time Protocol is used to synchronize clocks via computer network, then systems can be synchronized without physical connections, but synchronization precision deteriorates to greater than 5 milliseconds deviation

Engineering Contradiction:
Improvesynchronization without physical connectionsVSAvoidsynchronization precision
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary synchronization signal transmitted through the electrical power network to mediate between distributed loudspeaker systems. This power line carrier communication serves as a mediator that carries precise timing information without requiring direct physical audio connections between systems, achieving both wireless independence and high precision synchronization.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical/audio signal transmission methods with electromagnetic signal transmission through the electrical power network. By modulating synchronization data onto power line frequencies, the system substitutes physical audio cable connections with electrical infrastructure-based communication, achieving precise synchronization without mechanical linkages.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If each loudspeaker incorporates its own amplifier and operates independently, then system flexibility and adaptability improve, but synchronization precision deteriorates without physical synchronization links

Engineering Contradiction:
Improvesystem flexibilityVSAvoidsynchronization precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements a feedback mechanism where each loudspeaker system receives synchronization signals from a reference system via the power network, compares its own timing, and adjusts its clock accordingly. This closed-loop feedback ensures that independently operating amplifiers maintain precise synchronization while retaining their individual operational flexibility.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent makes the electrical power network serve multiple functions: it provides both electrical power to the loudspeaker systems and serves as a communication channel for synchronization signals. This multi-functionality allows independently amplified systems to achieve synchronization without adding separate physical connection infrastructure, maintaining flexibility while enabling precise timing coordination.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3257254B1Method for synchronising and rendering multimedia streams
Publication Date: 2023.01.04 DEVIALET
  • EP3257254B1 patent drawingFigure 1
  • EP3257254B1 patent drawingFigure 2
  • EP3257254B1 patent drawingFigure 3

AI summary

The present invention concerns a method for synchronising at least two systems for rendering multimedia streams, the method comprising: - detecting a pulse of a same signal of fixed frequency by each rendering system and by a main clock system, - generating a main clock signal and a dependent clock signal, - estimating a main local date of reception of the next pulse and a dependent local date of reception of the next pulse, - calculating the difference between the main local date and the dependent local date, - iterating the preceding steps until a first condition concerning the calculated differences is met, - receiving a multimedia stream, by each of the rendering systems, - sending a rendering date, and - calculating an effective date for the rendering of the multimedia stream.