Microphone Assembly Echo Rejection via Frequency Segregation
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Solution Overview
Problem
Audio endpoints with vertically aligned microphones experience significant echo issues due to acoustic coupling, leading to subpar sound quality and failure to meet telecommunication standards, as traditional echo cancellation techniques are ineffective at high sound pressure levels.
Innovation Solution
The design incorporates vertically aligned uni-directional microphones with different aperture sizes and frequency ranges, along with a two-way acoustic architecture, where the upper speaker handles higher frequencies and the lower speaker handles lower frequencies, to reduce echo through combing effects and phase cancellations, and utilizes an echo cancellation circuit with filtering to process signals effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the distance between speaker and microphone is reduced to make the audio endpoint smaller, then the device size is reduced, but the acoustic coupling between speaker and microphone increases causing greater echo
Solution Approach 1:
The audio endpoint is divided into distinct upper and lower sections with speakers and microphones segregated by vertical position and frequency range. The upper speaker handles high frequencies while the lower speaker handles low frequencies, creating spatial and spectral separation that reduces acoustic coupling and echo between microphones and speakers.
Solution Approach 2:
Different frequency ranges are assigned to different spatial locations within the device. The upper speaker assembly is optimized for high frequencies and the lower speaker assembly for low frequencies, creating localized acoustic zones that minimize cross-interference and echo while maintaining compact overall dimensions.
2Object-generated harmful factors
If traditional echo cancellation techniques are used, then echo suppression is achieved, but the techniques are ineffective at high sound pressure levels resulting in subpar sound quality
Solution Approach 1:
The design converts the potential harm of acoustic coupling into a beneficial frequency-segregated architecture. By assigning specific frequency ranges to specific speaker-microphone pairs, the system transforms what could be echo-prone close proximity into an advantage for frequency-specific acoustic zones, enabling effective echo cancellation even at high sound pressure levels.
Solution Approach 2:
The system changes the operational parameters by implementing frequency-range separation where the upper speaker handles frequencies above a threshold and the lower speaker handles frequencies below the threshold. This parameter-based segmentation allows echo cancellation to work effectively across different volume levels by processing different frequency bands independently.
3Device complexity
If vertically aligned microphones are used, then the device structure is simplified, but significant echo issues occur due to acoustic coupling
Solution Approach 1:
The vertically aligned microphone structure is segmented into upper and lower pairs, each associated with a specific frequency range. The upper microphone pair captures high frequencies from the upper speaker while the lower microphone pair captures low frequencies from the lower speaker, maintaining structural simplicity while eliminating echo through frequency-based separation.
Solution Approach 2:
The vertical alignment provides multi-functionality by enabling both compact structure and effective echo cancellation when combined with frequency-range separation. The same vertical space serves both structural simplicity and acoustic performance goals by processing different frequency bands through different microphone-s speaker pairs.
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 configuration significantly reduces echo pressure levels, allowing for full-duplex communication at maximum volume while improving voice quality and meeting telecommunication standards without increasing CPU power requirements.
Implementation Method 1
the closer the distance between the speaker(s) and microphone(s), the higher the acoustic coupling between them
Implementation Method 2
utilizes an echo cancellation circuit with filtering to process signals effectively
Data Source
AI summary
Presented herein is an audio endpoint for telecommunication operations with increased echo rejection. According to one example, the audio endpoint includes a housing body, an upper speaker assembly, a lower speaker assembly, and at least one microphone assembly. The upper speaker assembly is disposed near a top portion of the housing body and has an effective frequency range above a first frequency. The lower speaker assembly is disposed near a bottom portion of the housing body and has an effective frequency range below a second frequency. The microphone assembly includes a first microphone element and a second microphone element. The first microphone element is above the second microphone element so that they are vertically aligned. The first microphone element has an effective frequency range below the first frequency and the second microphone element has an effective frequency range above the second frequency.