Spectral Mixing of Accelerometer and Microphone Signals
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Solution Overview
Problem
Existing voice communication systems in mobile devices suffer from environmental noise interference, such as wind noise and background sounds, which degrade speech quality during hands-free operations.
Innovation Solution
The system employs spectral mixing of signals from an accelerometer in earbuds with acoustic signals from a microphone array, using a pitch estimate generated from the accelerometer output to enhance voice quality by isolating and suppressing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If spectral mixing of accelerometer and microphone signals is performed, then environmental noise is reduced and voice quality is improved, but device complexity increases due to additional signal processing components
Solution Approach 1:
The patent combines accelerometer signals and microphone signals through spectral mixing to create an enhanced voice output. The spectral mixer merges these two signal sources by aligning and scaling them based on their respective power levels, thereby reducing environmental noise while maintaining voice quality without requiring separate processing paths for each signal type.
Solution Approach 2:
The system dynamically adjusts the scaling factors of the accelerometer and microphone signals based on their power ratios. By changing the amplitude parameters of the signals according to their relative strengths, the system optimizes the mixing ratio in real-time, allowing the spectral mixer to adapt to varying acoustic environments and maintain optimal noise reduction performance.
2Measurement precision
If accelerometer signals are scaled based on power ratio, then signal alignment is improved, but processing time increases due to additional scaling calculations
Solution Approach 1:
The system performs preliminary power ratio calculations between the accelerometer and microphone signals before the spectral mixing process. By pre-computing the scaling factors based on the power levels of the individual signals, the system prepares the necessary alignment parameters in advance, which then can be applied efficiently during the actual mixing operation without requiring complex real-time calculations.
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 approach effectively reduces environmental noise interference, improving the intelligibility of user speech by aligning and scaling the accelerometer and microphone signals, resulting in enhanced voice communication quality.
Implementation Method 1
The inertial sensor may detect vibration of the user's vocal chords based on vibrations in bones and tissue of the user's head
Implementation Method 2
A spectral mixer included in the mobile device may then perform spectral mixing of the output from the inertial sensor with the acoustic signals from the microphone array to generate a mixed signal
Data Source
AI summary
A method of improving voice quality in a mobile device starts by receiving acoustic signals from microphones included in earbuds and the microphone array included on a headset wire. The headset may include the pair of earbuds and the headset wire. An output from an accelerometer that is included in the pair of earbuds is then received. The accelerometer may detect vibration of the user's vocal chords filtered by the vocal tract based on vibrations in bones and tissue of the user's head. A spectral mixer included in the mobile device may then perform spectral mixing of the scaled output from the accelerometer with the acoustic signals from the microphone array to generate a mixed signal. Performing spectral mixing includes scaling the output from the inertial sensor by a scaling factor based on a power ratio between the acoustic signals from the microphone array and the output from the inertial sensor. Other embodiments are also described.