Noise Reduction Device Phase Alignment for Disparate Microphone Locations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional noise reduction devices are ineffective in reducing noise at a sound reception location when the location of the sound receiver and the microphone are different, as they fail to account for the phase differences between the cancellation sound and noise at these disparate locations.
Innovation Solution
A noise reduction device that includes a standard signal generator, an adaptive filter unit, correctors, and a filter coefficient update unit, which generates a cancellation sound by applying filter coefficients to a standard signal and corrects error signals based on transfer characteristics and predetermined parameters to effectively reduce noise at the sound reception location, even when it differs from the sound collection location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional noise reduction device uses a single microphone at a fixed location to generate cancellation sound, then the device structure is simple, but the noise reduction effectiveness deteriorates when the sound reception location differs from the sound collection location
Solution Approach 1:
The patent segments the sound field into multiple locations by deploying multiple microphones at different positions. Each microphone captures noise characteristics specific to its location, enabling the system to generate cancellation sounds that are effective at multiple sound reception locations simultaneously, thereby resolving the contradiction between noise reduction effectiveness and device complexity
Solution Approach 2:
The patent combines signals from multiple microphones through signal processing to generate a composite cancellation sound. By merging the noise information from different locations and processing it through an adaptive filter, the system creates a unified cancellation signal that addresses noise at multiple locations, achieving improved noise reduction effectiveness without proportionally increasing device complexity
2Measurement precision
If the device uses adaptive filter to update coefficients based on error signal from one location, then the processing is simple, but the phase alignment deteriorates at different locations
Solution Approach 1:
The patent implements feedback mechanisms where error signals from multiple locations are fed back to continuously update the adaptive filter coefficients. This feedback loop ensures that the cancellation sound maintains proper phase alignment at different locations by constantly adjusting the filter parameters based on actual performance at each location
Solution Approach 2:
The patent employs dynamic signal processing where the adaptive filter coefficients are continuously adjusted based on incoming error signals from multiple microphones. This dynamic adaptation allows the system to maintain precise phase alignment at different locations by responding to changing acoustic conditions in real-time
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 device effectively reduces noise at the sound reception location by adjusting the gain and phase of the cancellation sound to align with the noise, ensuring that the phase difference between the cancellation sound and noise is 180 degrees, thereby minimizing residual noise.
Implementation Method 1
the phase difference between the cancellation sound and noise is 180 degrees, thereby minimizing residual noise
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3B
AI summary
A noise reduction device includes a second corrector that generates a correction signal by correcting an output signal or a standard signal by a predetermined parameter and adds the generated correction signal to an error signal, to generate a corrected error signal approximating the error signal to an error signal indicating a residual sound occurring in a sound reception location.