Stereo Microphone Directivity Control via Phase Difference
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Solution Overview
Problem
Existing sound collection devices using stereo microphones require multiple microphones for noise reduction and lack effective control over sound collection directivity, leading to inefficiencies in noise cancellation and directional control.
Innovation Solution
A sound collecting device with stereo microphones arranged obliquely to the optical axis and at different distances, utilizing a phase difference detection circuit and processor for directivity control, allowing for adjustable sound collection based on phase differences between microphone signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple microphones are used for noise cancellation, then noise reduction capability is improved, but device complexity increases
Solution Approach 1:
The patent combines the functions of noise reduction and directivity control into a single stereo microphone system. By processing signals from two microphones arranged in specific geometries (orthogonal and oblique configurations), the system achieves both noise cancellation and directional sound collection without requiring separate dedicated microphones for each function.
Solution Approach 2:
The stereo microphone system performs multiple functions simultaneously: it collects sound from specific directions, reduces noise from other directions, and provides stereo audio output. The same two microphones serve both as noise reduction elements and as directivity control elements, eliminating the need for separate specialized microphones.
2Ease of operation
If simple directivity switching is implemented, then ease of operation is improved, but adaptability to different sound collection states deteriorates
Solution Approach 1:
The patent implements dynamic directivity control that automatically adjusts sound collection characteristics based on the acoustic environment. The system calculates phase differences between microphone signals and dynamically adjusts weighting coefficients to optimize directivity for the current sound collection state, rather than using fixed preset modes.
Solution Approach 2:
The system uses feedback from phase difference calculations to automatically adjust directivity parameters. By continuously monitoring the phase relationship between signals from the two microphones, the system adapts its sound collection pattern to maintain optimal performance for the current acoustic situation.
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
Enables efficient noise reduction and precise control over sound collection directivity, improving the quality of speech signals by attenuating noise from unwanted directions and focusing on specific sound sources.
Implementation Method 1
a phase difference detection circuit that detects phase difference between two speech signals that have been converted by the first microphone and the second microphone
Data Source
AI summary
A sound collecting device, comprising stereo microphones that are arranged apart in a direction intersecting obliquely with respect to a direction that is vertical to a direction connecting the user and an subject, and arranged at different distances in the direction that joins the user and the subject, and a processor for directivity control that adjust directivity of speech signals from the stereo microphones.