Microphone Array Echo Cancellation via Signal Integration
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Solution Overview
Problem
Existing steerable superdirectional microphone systems are complex and costly due to the need for separate echo cancellers for each microphone unit, which increases complexity and degrades the output signal.
Innovation Solution
A microphone system comprising a microphone array with at least two units that generates a monopole and dipole response, integrates the dipole response, performs echo cancellation on the integrated dipole response before combining it with the monopole response, and uses adaptive filters to maintain signal quality and reduce complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate echo cancellers are provided for each microphone unit, then echo cancellation performance is improved, but device complexity and costs increase
Solution Approach 1:
The patent combines multiple echo cancellation functions into a single shared echo canceller that processes the combined output of multiple microphone units. Instead of having separate echo cancellers for each microphone, the system merges the signals from multiple microphones and applies a single echo cancellation filter to the combined signal, thereby reducing system complexity while maintaining echo cancellation effectiveness.
Solution Approach 2:
The single echo canceller in the patent serves multiple functions by processing the combined output signals from multiple microphone units. This universal approach allows one echo cancellation unit to handle echo removal for all microphones simultaneously, eliminating the need for multiple dedicated echo cancellers and reducing overall system complexity.
2Reliability
If multiple microphones are used to increase SNR, then signal quality is improved, but device complexity increases
Solution Approach 1:
The patent combines the output signals from multiple microphone units and processes them through a single shared echo canceller and subsequent combination unit. This merging approach allows the system to leverage the improved signal-to-noise ratio provided by multiple microphones while avoiding the complexity increase that would result from providing separate processing chains for each microphone.
3Reliability
If echo cancellation is applied to each primary signal, then echo removal is improved, but misadjustment errors increase especially at lower frequencies
Solution Approach 1:
The patent applies the echo cancellation filter to the combined output signal of multiple microphone units before the signals are fully processed and combined. This preliminary application of echo cancellation to the aggregated signal allows the system to correct echo effects at an earlier stage, preventing misadjustment errors from propagating through subsequent processing stages, particularly at lower frequencies where such errors would be most problematic.
Data Source
AI summary
A microphone system is provided, wherein the microphone system comprises a microphone array comprising a plurality of microphone units each adapted to generate a primary signal indicative of an acoustic wave received from the respective microphone unit, a first echo cancellation unit, an integrator unit, and a combination unit, wherein the microphone system is adapted to generate a first dipole response and a monopole response from the primary signals, wherein the integrator unit is adapted to generate a first integrated dipole response by integrating the first dipole response, wherein the first echo cancellation unit is adapted to generate a first echo cancelled integrated dipole response from the first integrated dipole response, and wherein the combination unit is adapted to combine the monopole response and the first echo cancelled integrated dipole response.