Microphone Mechanical Echo Cancellation Using Accelerometer Intermediary
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As wearable audio systems shrink in size, mechanically isolating microphones from driver vibrations becomes increasingly difficult, limiting design flexibility and increasing costs due to traditional mechanical isolation constraints.
Innovation Solution
The integration of inertial measurement units (IMUs) or accelerometers with microphones, allowing for mechanical echo cancellation (MEC) by processing vibrational data, which enables positioning of microphones and drivers on a shared substrate without traditional design restraints, and the use of operational amplifiers to subtract accelerometer signals from microphone signals in analog form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If microphones and drivers are positioned close together to reduce device size, then device compactness is improved, but mechanical coupling between microphones and driver increases causing vibration interference
Solution Approach 1:
An accelerometer is introduced as an intermediary component to detect mechanical vibrations from the driver. The accelerometer measures the vibration signal, which is then processed through a transfer function to model the mechanical coupling path. This intermediary allows the system to characterize and subsequently cancel the harmful mechanical coupling without requiring physical isolation between the driver and microphone.
Solution Approach 2:
The patent replaces traditional mechanical isolation structures with a signal processing-based solution. Instead of using physical dampers, isolation mounts, or spatial separation to reduce mechanical coupling, the system uses digital signal processing to measure, model, and subtract the vibration signal from the microphone output. This substitution eliminates the need for complex mechanical isolation designs.
2Object-affected harmful factors
If traditional mechanical isolation is implemented to prevent vibration coupling, then mechanical coupling interference is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent replaces traditional mechanical isolation structures with a signal processing-based solution. Instead of using physical dampers, isolation mounts, or spatial separation to reduce mechanical coupling, the system uses digital signal processing to measure, model, and subtract the vibration signal from the microphone output. This substitution eliminates the need for complex mechanical isolation designs.
Solution Approach 2:
The system uses the accelerometer mounted on the same substrate as the driver and microphone to self-characterize the mechanical coupling path. The transfer function is determined by measuring the relationship between the accelerometer signal and the microphone signal, allowing the system to adapt to variations in mounting conditions and substrate properties without requiring precise mechanical isolation design.
3Ease of manufacture
If microphones and drivers are positioned on a shared substrate without isolation, then ease of manufacture is improved, but mechanical coupling causes vibration interference in audio signals
Solution Approach 1:
An accelerometer is introduced as an intermediary component to detect mechanical vibrations from the driver. The accelerometer measures the vibration signal, which is then processed through a transfer function to model the mechanical coupling path. This intermediary allows the system to characterize and subsequently cancel the harmful mechanical coupling without requiring physical isolation between the driver and microphone.
Solution Approach 2:
The patent replaces traditional mechanical isolation structures with a signal processing-based solution. Instead of using physical dampers, isolation mounts, or spatial separation to reduce mechanical coupling, the system uses digital signal processing to measure, model, and subtract the vibration signal from the microphone output.
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 cancels mechanical vibrations from audio signals, improving noise cancellation and natural language processing capabilities while reducing design complexity and size constraints.
Implementation Method 1
vibrations generated by the driver may propagate through the structure of the wearable component or the substrate
Implementation Method 2
The package may also include an operational amplifier coupled to receive the output of the microphone and accelerometer
Implementation Method 3
an operational amplifier coupled to receive the output of the microphone and accelerometer such that the operational amplifier may subtract the accelerometer signal from the microphone signal
Data Source
AI summary
An audio system that includes an IMU or accelerometer in physical proximity to a microphone and a driver. The signal generated by the IMU or accelerometer may be used to filter the audio signal generated by the microphone with respect to mechanically coupling between the driver outputting sound and the microphone via a shared structure. In some cases, an accelerometer may be incorporated into a package of the microphone to provide analog-based filtering prior to converting the audio signal of the microphone to a digital format.