Bone and Air Conduction Signal Delay for Sound Position Alignment
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Solution Overview
Problem
Existing acoustic devices using both bone conduction and air conduction methods suffer from sound deviation due to asynchronous generation of sound waves, leading to a perception of sound position bias, which degrades user experience.
Innovation Solution
The acoustic device employs a signal processing method that delays the transmission of one driving signal relative to the other to ensure a time difference of less than or equal to 100 microseconds between the generation of bone conduction and air conduction sound waves, particularly at mid-frequency bands, thereby synchronizing the sound output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bone conduction and air conduction sound waves are generated simultaneously, then the acoustic device can provide comprehensive sound coverage, but sound deviation occurs due to asynchronous generation
Solution Approach 1:
The patent applies preliminary action by calculating and applying a time delay to one of the driving signals before it is sent to the corresponding sound component. The signal processing circuit determines the time delay based on the difference in time delays between the bone conduction and air conduction paths, ensuring that both sound waves arrive at the user's ear simultaneously. This preliminary adjustment of the signal timing resolves the sound deviation issue while maintaining comprehensive sound coverage.
2Reliability
If different time delays are compensated for bone conduction and air conduction paths, then sound synchronization is achieved, but signal processing complexity increases
Solution Approach 1:
The patent applies parameter changes by adjusting the time delay parameter of the driving signals based on the measured or pre-determined time delay difference between the bone conduction and air conduction paths. The signal processing circuit modifies the timing parameter of one signal relative to the other, transforming the asynchronous sound wave generation into synchronous generation. This parameter adjustment approach achieves sound synchronization while keeping the processing circuit relatively simple.
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
This synchronization effectively avoids sound deviation, providing a better listening experience by ensuring synchronized sound perception across various frequency ranges.
Implementation Method 1
a bone conduction sound component, configured to generate a first time delay when converting a first driving signal into a bone conduction sound wave
Implementation Method 2
an air conduction sound component, configured to generate a second time delay when converting a second driving signal into an air conduction sound wave
Implementation Method 3
one of the first driving signal and the second driving signal is delayed relative to the other, so that at least at partial frequencies the bone conduction sound wave is generated at a first time, the air conduction sound wave is generated at a second time, and a time difference between the first time and the second time is less than or equal to 100 microseconds
Data Source
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Figure 5~6A
AI summary
The embodiments of this specification provide an acoustic device and a signal processing method, the bone conduction sound component of the acoustic device generates a first delay when converting the first driving signal into bone conduction sound waves, the air conduction sound component generates a second delay when converting the second driving signal into air conduction sound waves, the absolute value of the difference between the second delay and the first delay is greater than 100 microseconds, the signal processing circuit obtains an audio signal during operation, generates a first driving signal based on a first component of the audio signal and sends it to the bone conduction sound component, generates a second driving signal based on a second component of the audio signal and sends it to the air conduction sound component, one of the first driving signal and the second driving signal is delayed relative to the other, so that the time difference between the generation time of the bone conduction sound waves and the generation time of the air conduction sound waves at least at partial frequencies is less than or equal to 100 microseconds. The above solution can avoid sound deviation problems.