Multi-Device Audio Localization Without Synchronized Clocks
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Solution Overview
Problem
Existing systems struggle to synchronize audio output across multiple devices without synchronized clocks, leading to audio quality issues in flexible home theater setups.
Innovation Solution
A system for multi-device localization and ranging that generates a device map by determining relative directions and distances using calibration tones, even when devices lack synchronized clocks, allowing for optimized audio rendering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electronic devices are used to capture and process audio data, then audio processing capability is improved, but synchronization accuracy deteriorates due to lack of synchronized clocks
Solution Approach 1:
The patent introduces a localization server as an intermediary that receives timing information from multiple electronic devices, determines relative timing relationships between devices, and generates synchronization adjustments. This mediator enables synchronization without requiring the devices themselves to have synchronized clocks, resolving the contradiction between multi-device audio processing capability and synchronization accuracy.
Solution Approach 2:
The system implements feedback by having devices transmit timing information about calibration tones to the localization server, which then calculates timing differences and provides synchronization adjustments. This feedback loop enables continuous refinement of synchronization across multiple devices with independent clocks, maintaining both processing capability and accuracy.
2Ease of operation
If devices without synchronized clocks are used, then device flexibility and ease of setup are improved, but audio quality deteriorates due to timing discrepancies
Solution Approach 1:
The patent applies preliminary action by first having each device transmit timing information about calibration tones before normal audio operation begins. The localization server uses this preliminary timing data to calculate relative timing relationships and generate synchronization adjustments, which are then applied to ensure audio quality while allowing devices to operate independently without pre-synchronized clocks.
Solution Approach 2:
The system changes the timing parameters of audio playback by calculating timing differences between devices and applying compensatory adjustments. This parameter modification enables devices with independent clocks to achieve synchronized audio output, maintaining both flexibility in device selection and reliability in audio quality.
3Measurement precision
If calibration tones are transmitted sequentially to determine device positions, then localization accuracy is improved, but calibration time increases
Solution Approach 1:
The patent employs periodic action by having devices transmit calibration tones at multiple distinct time periods rather than sequentially one after another. This allows the localization server to receive timing information from multiple devices simultaneously or in overlapping intervals, calculating relative timing relationships more efficiently while maintaining localization accuracy through multiple measurement points.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables synchronized audio playback across devices with varying positions and types, enhancing audio quality by adjusting playback audio based on device locations and characteristics.
Implementation Method 1
determine timing information associated with a time difference of arrival of the audible sounds
Implementation Method 2
determine distance values between the plurality of devices based on the timing information
Data Source
AI summary
A system configured to create a flexible home theater group using a variety of different devices. To enable synchronized audio output, the system performs device localization to generate map data representing locations of the devices. The system determines distance values between devices using timing information generated during calibration even when the devices themselves may not have synchronized clocks. During calibration, each device will generate a calibration tone in a particular order, enabling listening devices to detect the calibration tone and determine a relative direction of the output device. The listening devices also generate timing information indicating when each calibration tone was detected which can be used to determine a propagation delay that corresponds to a distance between the output device and the listening device. Using the relative directions and the distance values, the primary device can generate a device map that enables the home theater to render output audio correctly.