Asymmetric Multi-Ringed Microphone Array for Compact Devices
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Solution Overview
Problem
Current circular differential microphone arrays (CDMAs) face limitations in compact design due to the requirement of identical numbers of microphones on each ring, leading to impractical inner ring configurations and alignment constraints, which restrict their deployment in compact devices and hinder noise reduction and sound source localization effectiveness.
Innovation Solution
The multi-ringed circular differential microphone array (MR-CDMA) allows varying numbers of microphones on different rings, eliminating the need for alignment, and uses a beamformer structure approximated by Jacobi-Anger expansions to achieve flexible design and improved noise suppression, enabling more microphones on outer rings and fewer on inner rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If identical numbers of microphones are used on each ring of the circular differential microphone array, then the beamformer can maintain frequency-invariant beam patterns, but the inner ring configuration becomes impractical and alignment constraints increase
Solution Approach 1:
The patent applies asymmetry by allowing different numbers of microphones on different rings of the circular differential microphone array. Specifically, outer rings can have more microphones than inner rings, breaking the traditional symmetric constraint. This asymmetric configuration enables practical compact designs while the beamformer processing maintains frequency-invariant beam patterns through appropriate weight optimization.
2Adaptability or versatility
If more microphones are placed on outer rings and fewer on inner rings, then the array becomes more practical for compact devices, but the traditional beamformer structure cannot maintain frequency-invariant performance
Solution Approach 1:
The patent applies parameter changes by optimizing the beamformer weights as a function of frequency and direction. The weight vectors are designed to compensate for the non-uniform microphone distribution across rings, ensuring that the beam pattern remains frequency-invariant despite the varying number of microphones on each ring. This maintains noise reduction and sound source localization effectiveness while enabling compact flexible configurations.
3Stability of the object's composition
If alignment constraints are imposed on microphones across different rings, then the array structure becomes more regular, but the device size increases and compact deployment is restricted
Solution Approach 1:
The patent eliminates the need for strict alignment constraints by adopting an asymmetric configuration where each ring can have a different number of microphones. The beamformer processing accounts for the specific positions and varying counts on each ring, allowing compact deployment without requiring microphones to be aligned across rings. This reduces device volume while maintaining array structure stability through computational methods.
Data Source
AI summary
A multi-ringed differential microphone array includes a first number of microphones situated along a first substantial circle having a first radius, a second number of microphones situated along a second substantial circle having a second radius, and a processing device, communicatively coupled to the first number microphones and the second number of microphones, to receive a plurality of electronic signals generated by the first number of microphones and the second number of microphones, determine a differential order (N) based on the second number, and execute an N-th order minimum-norm beamformer to calculate an estimate of the sound source based on the plurality of electronic signals.