TWS Earphone Audio Synchronization via Frequency Deviation Calibration
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Solution Overview
Problem
True wireless stereo (TWS) earphones face synchronization issues due to varying delays in wireless audio data transmission to the left and right earpieces, affecting precise audio playback.
Innovation Solution
The method involves a master and slave earphone configuration with timers and phase-locked loops, where a frequency deviation coefficient is calculated to calibrate the slave earphone's audio playback, ensuring synchronization by adjusting the audio data and playback phase-locked loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If wireless Bluetooth communication technology is used to transmit audio data to two earpieces separately, then the physical wire between earphones and audio source is eliminated, but synchronization delay occurs between left and right earpieces
Solution Approach 1:
The patent implements a feedback mechanism where the master earpiece continuously monitors its own playback timing and Bluetooth clock, then sends timing information to the slave earpiece. The slave earpiece uses this feedback to calculate frequency deviation and adjust its playback timing accordingly, achieving synchronization without physical wires.
Solution Approach 2:
The patent changes the parameter of clock frequency by calculating the frequency deviation coefficient between the master and slave Bluetooth clocks. By dynamically adjusting the slave earpiece's playback timing based on this frequency deviation parameter, the system achieves precise audio synchronization while maintaining wireless operation.
2Adaptability or versatility
If separate audio data transmission to left and right earpieces is implemented, then true wireless stereo functionality is achieved, but playback synchronization precision deteriorates
Solution Approach 1:
The patent performs preliminary timing calibration by having the master earpiece send its first timer value and Bluetooth clock information to the slave earpiece before audio playback begins. This preliminary action establishes a reference timing relationship that enables precise synchronization throughout the audio playback process.
Solution Approach 2:
The patent replaces the mechanical timing synchronization method (used in wired earphones) with an electronic/software-based timing calibration system. By using timer values, Bluetooth clock synchronization, and frequency deviation calculation through software algorithms, the system achieves precise timing accuracy without mechanical connections.
3Manufacturing precision
If timer and phase-locked loop adjustment is performed to achieve precise synchronization, then audio playback synchronization is improved, but system complexity increases
Solution Approach 1:
The patent makes the first timer serve multiple functions: it records the master earpiece's audio playback position, provides timing reference for synchronization calculations, and enables frequency deviation measurement. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in system complexity while achieving precise synchronization.
Data Source
AI summary
The present disclosure provides a method and system for synchronous audio playback of TWS earphones, The TWS earphones include a master earphone and a slave earphone; both the master earphone and the slave earphone include a first timer, a second timer, an audio DAC, and an audio playback phase-locked loop; the first timer and the second timer of the master earphone are respectively used to collect a real-time audio playback position of the master earphone and a public Bluetooth clock; the first timer and the second timer of the slave earphone are respectively used to collect a real-time audio playback position of the slave earphone and a local Bluetooth clock; the slave earphone calibrates audio data in the audio DAC, and the first timer and the audio playback phase-locked loop of the slave earphone, to achieve synchronization between the master earphone and the slave earphone.