Multi-Device Audio Playback Synchronization Using Ultrasound Feedback
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Solution Overview
Problem
Multiple electronic devices in the same space playing audio content with inconsistent playback times, leading to interference and reduced clarity in conference calls due to Internet or system latency.
Innovation Solution
A method and control circuit utilizing a master device to receive audio data, generate ultrasound data, and estimate delay values to synchronize playback across slave devices using calibration and delay circuits, compensating for playback differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple electronic devices independently receive and play audio data from a far-end device, then each device can independently process audio content, but playback time points become inconsistent causing audio interference and reduced clarity
Solution Approach 1:
The master device receives audio data from slave devices via ultrasound, compares it with its own playback, and adjusts its playback timing based on the detected delay. This feedback loop ensures synchronized playback across all devices, resolving the time inconsistency problem while maintaining audio clarity
Solution Approach 2:
The system dynamically adjusts the playback timing parameter of the master device based on the detected delay value. By changing the playback time parameter in response to measured conditions, the system achieves synchronized playback without requiring all devices to operate at fixed predetermined times
2Reliability
If a master device is introduced to distribute audio data to slave devices, then playback synchronization can be achieved, but device complexity increases
Solution Approach 1:
The master device acts as an intermediary that coordinates playback timing among multiple devices. It receives audio data, determines playback timing, and distributes this timing information to slave devices. This intermediary approach achieves synchronization without requiring complex peer-to-peer coordination between all devices
Solution Approach 2:
The system replaces complex mechanical synchronization mechanisms with acoustic ultrasound signals for timing communication. The master device uses its microphone to receive ultrasound from slave devices, enabling timing synchronization through acoustic wave propagation rather than complex electronic handshaking protocols
3Measurement precision
If ultrasound data is generated and transmitted by slave devices for delay estimation, then playback delay can be measured, but additional energy consumption occurs
Solution Approach 1:
The system changes the frequency parameter of the audio signal to ultrasound frequencies for delay measurement purposes. By modulating the audio data onto ultrasound carriers, the system achieves precise delay estimation while using the same hardware components, minimizing additional energy consumption
Solution Approach 2:
The slave devices use their existing speakers and audio processing components to generate and transmit ultrasound data. The same hardware that plays audio content is also used for timing synchronization, eliminating the need for separate dedicated timing hardware and reducing overall energy consumption
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
Synchronizes playback across multiple electronic devices without significant additional cost, reducing interference and improving audio clarity in conference settings.
Implementation Method 1
the at least one slave device generates ultrasound data according to the slave audio data, and makes a speaker of the at least one slave device play the slave audio data and the ultrasound data
Implementation Method 2
utilizing a calibration circuit of the master device to estimate a delay value between the ultrasound data received by the microphone of the master device and the master audio data
Data Source
AI summary
A method and a control circuit for performing synchronization on playback of multiple electronic devices are provided, where the multiple electronic devices include a master device and a slave device. The method includes: utilizing the master device to receive audio data from a far-end device to be master audio data, and transmitting the master audio data to the slave device to be slave audio data, where the slave device generates ultrasound data according to the slave audio data, to make the slave device play the slave audio data and the ultrasound data; utilizing a calibration circuit to estimate a delay value between the ultrasound data received by a microphone of the master device and the master audio data; and utilizing a delay circuit to control a delay of the master audio data according to the delay value, to generate master output audio data for being played by the master device.