Bluetooth Earbud Clock Synchronization Through Phase Compensation
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Solution Overview
Problem
Bluetooth earbuds experience asynchronous audio playback due to natural deviations in crystal oscillator frequencies between the master and slave earbuds, leading to perceptible play asynchrony.
Innovation Solution
A frequency adjustment method and apparatus for Bluetooth earbuds that involves receiving signaling packets from the master earbud, calculating phase differences, and performing rapid phase compensation and synchronization adjustments on the slave earbud's clock frequency to align it with the master earbud.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rapid phase compensation processing is performed on the slave earbud's clock frequency, then the relative phase difference between earbuds is reduced, but the device complexity increases
Solution Approach 1:
The slave earbud receives signaling packets from the master earbud containing Bluetooth clock information, calculates the phase difference between its own clock and the master's clock, and uses this feedback to automatically adjust its clock frequency. This closed-loop feedback mechanism enables automatic synchronization without manual intervention.
Solution Approach 2:
The slave earbud autonomously performs frequency adjustment by receiving phase difference information from the master earbud, calculating the required adjustment, and modifying its own clock frequency. The system serves itself by eliminating the need for external calibration equipment or manual intervention.
2Reliability
If the clock frequency of the slave earbud is adjusted frequently to maintain synchronization, then the audio playback synchronization is improved, but the energy consumption increases
Solution Approach 1:
The master earbud periodically transmits signaling packets containing its Bluetooth clock information to the slave earbud at predetermined intervals. This periodic transmission allows the slave earbud to continuously monitor and adjust its phase without requiring constant active communication, reducing overall energy consumption while maintaining synchronization.
3Measurement precision
If the phase compensation threshold is set low for precise synchronization, then the audio play asynchrony is reduced, but the frequency adjustment operations increase
Solution Approach 1:
The system applies full frequency adjustment operations only when the phase difference exceeds a predetermined threshold. For smaller phase differences within the threshold range, no adjustment is performed. This partial action approach prevents unnecessary frequency adjustments while still achieving sufficient synchronization for audio playback.
Data Source
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AI summary
The present application relates to a frequency adjustment method and apparatus, Bluetooth earphones, a storage medium, and a program product. The method comprises: receiving a signaling packet periodically sent by a master earphone; acquiring a Bluetooth clock of a corresponding slave earphone according to a target sample point identifier in the signaling packet; calculating a difference between a Bluetooth clock of the master earphone and the Bluetooth clock of the slave earphone to obtain a first phase difference; determining the first phase difference between the Bluetooth clock of the slave earphone and the Bluetooth clock of the master earphone; if the first phase difference meets a phase compensation condition, performing fast phase compensation processing on a clock frequency of the slave earphone according to the first phase difference; after the clock frequency of the slave earphone is adjusted, determining a second phase difference between the Bluetooth clock of the slave earphone and the Bluetooth clock of the master earphone again; and adjusting the clock frequency of the slave earphone again according to the first phase difference and the second phase difference. By using the method, the playback of a pair of earphones in the Bluetooth earphones can be accurately synchronized.