Directional Acoustic Sensor Noise Attenuation via Resonance Summation
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Solution Overview
Problem
Directional acoustic sensors face challenges in accurately recognizing user voices due to interference from noise sources, such as TVs or smart speakers, as they often have difficulty distinguishing between target and noise sound sources, especially when noise sources are closer than the target sources, leading to reduced signal-to-noise ratios.
Innovation Solution
A directional acoustic sensor with multiple resonance units arranged at different angles and a signal processor that calculates the sum or difference of output signals from these units to adjust directional characteristics and attenuate noise signals, enhancing the attenuation ratio in noise directions beyond 20 dB, thereby improving signal recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single acoustic sensor is used to detect sound, then the device complexity is low, but the ability to distinguish between target and noise sound sources deteriorates
Solution Approach 1:
The acoustic sensing system is divided into multiple resonance units (first resonance unit and second resonance unit) with different directional characteristics. Each unit independently detects acoustic signals from different spatial directions, enabling the system to distinguish between target sound sources and noise sources by comparing outputs from segmented sensing elements.
Solution Approach 2:
The patent introduces spatial dimensionality by arranging resonance units at different orientations (e.g., 45 degrees and 135 degrees relative to a reference axis). This spatial arrangement creates directional sensitivity along different axes, transforming a single-point detection into a multi-directional sensing capability that enables noise rejection through spatial filtering.
2Reliability
If multiple resonance units with different directionalities are arranged to improve noise attenuation, then the signal-to-noise ratio improves, but the device complexity increases
Solution Approach 1:
The patent combines outputs from multiple resonance units through mathematical operations (summation and differencing) to achieve noise attenuation. By merging the signals in specific ways—adding signals from units with complementary directional patterns and subtracting signals from units with opposing patterns—the system enhances target signals while canceling noise signals from specific directions.
Solution Approach 2:
The signal processor continuously adjusts the weighting coefficients applied to each resonance unit's output based on the relative strengths and phases of received signals. This feedback mechanism dynamically optimizes the combination of signals to maximize noise attenuation while preserving target speech, adapting to changing acoustic environments in real-time.
3Adaptability or versatility
If resonance units are arranged at specific angles to enhance directional characteristics, then the directional selectivity improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs adjustable weighting coefficients that can be programmed into the signal processor to compensate for deviations in the physical arrangement of resonance units. By changing these software parameters rather than requiring precise mechanical adjustments, the system maintains optimal directional characteristics even when manufacturing tolerances cause slight angular variations in unit placement.
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
The solution effectively attenuates noise signals in specific directions, enhancing the signal-to-noise ratio and improving the sensor's ability to accurately recognize user voices by adjusting directional characteristics and processing signals to isolate desired acoustic inputs.
Implementation Method 1
a directional acoustic sensor that detects an acoustic signal by converting a mechanical movement due to a pressure difference to an electrical signal
Implementation Method 2
converting a mechanical movement due to a pressure difference to an electrical signal
Data Source
AI summary
Disclosed are a directional acoustic sensor, a method of adjusting directional characteristics using the directional acoustic sensor, and a method of attenuating an acoustic signal in a specific direction using the directional acoustic sensor. The directional acoustic sensor includes a plurality of resonance units arranged to have different directionalities and a signal processor configured to adjust directional characteristics by calculating at least one of a sum of and a difference between outputs of the resonance units. In this state, the signal processor attenuates an acoustic signal in a specific direction by using a plurality of directional characteristics obtained by calculating at least one of the sum of and the difference between the outputs of the resonance units at a certain ratio.