External Sound Transmission in Earphones With Dual-Microphone Filtering
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Solution Overview
Problem
Existing earphones and headsets obstruct natural hearing of external sounds due to their placement between the ear and eardrum, necessitating the use of external microphones to input external sounds, which require complex filtering processes.
Innovation Solution
An electronic device equipped with an external microphone, an internal microphone, a first filter, a second filter, and a processor that estimates a passive feature based on signals from both microphones, identifies a target frequency response, and filters the signals sequentially through these filters to output external sounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If earphones or headsets are placed between the ear and eardrum to enable audio output, then audio transmission function is improved, but natural hearing of external sounds deteriorates
Solution Approach 1:
The audio system is segmented into multiple independent pathways: (1) external microphone capturing ambient sound, (2) internal microphone capturing body-coupled sound, (3) separate filter processing for each pathway, and (4) combined output. This segmentation allows simultaneous audio transmission and natural hearing without mutual interference.
Solution Approach 2:
The patent introduces an intermediary processing system that includes: (1) a first filter for processing external microphone signals, (2) a second filter for processing internal microphone signals, and (3) a combining mechanism that merges both processed signals. This intermediary system enables both blocked and body-coupled sound pathways to coexist and be heard naturally.
2Object-affected harmful factors
If external microphone is used to input external sounds, then natural hearing is improved, but filtering complexity increases
Solution Approach 1:
The patent merges two previously separate processing pathways into a unified system: (1) external microphone pathway with first filter, and (2) internal microphone pathway with second filter. By combining these pathways and their respective filtered outputs, the system achieves natural hearing with reduced overall filtering complexity compared to processing only external sounds.
Solution Approach 2:
The dual-microphone system serves multiple functions simultaneously: (1) capturing external ambient sound, (2) capturing body-coupled sound, (3) processing both signals through separate filters, and (4) combining them for comprehensive audio output. This multi-functionality reduces the need for complex single-pathway filtering.
3Manufacturing precision
If dual microphone system is implemented with sequential filtering, then sound quality is improved, but processing time increases
Solution Approach 1:
The patent applies preliminary filtering actions to both external and internal microphone signals before combining them. The first filter processes external microphone signals and the second filter processes internal microphone signals in parallel, preparing both signals in advance for combination. This preliminary processing reduces the computational burden and time required for final sound quality enhancement.
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
Enhances the natural hearing of external sounds by accurately filtering and amplifying ambient sounds, reducing noise interference, and improving sound quality for users.
Implementation Method 1
an external microphone; an internal microphone
Implementation Method 2
a first filter; a second filter; filter a third signal acquired through the external microphone through the first filter and the second filter sequentially
Data Source
AI summary
An electronic device includes: at least one speaker; an external microphone; an internal microphone; a first filter; a second filter; and at least one processor operatively connected to the at least one speaker, the external microphone, and the internal microphone, wherein the at least one processor is configured to: estimate a passive feature based on a first signal acquired through the external microphone and a second signal acquired through the internal microphone, identify a target frequency response for the passive feature based on a reference passive feature, and filter a third signal acquired through the external microphone through the first filter and the second filter sequentially and output the filtered third signal through the at least one speaker, wherein the second filter is based on the target frequency response.