Range Hood Noise Cancellation with Adaptive LMS Parameter Control
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Solution Overview
Problem
Conventional noise cancellation techniques struggle to accurately cancel noise that fluctuates due to changes in environmental conditions such as temperature and humidity, particularly in range hood devices.
Innovation Solution
A signal processing device and program that includes a sound cancelling filter with adaptive filter coefficients, updated using a Filtered-X Least Mean Square algorithm, and an update parameter adjustment mechanism to account for noise fluctuations, ensuring effective noise cancellation across varying environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed update parameter is used in the LMS algorithm, then the noise cancellation system is simple to operate, but it cannot accurately cancel noise that fluctuates with environmental conditions
Solution Approach 1:
The patent applies dynamics by making the update parameter variable rather than fixed. The parameter adjuster dynamically changes the update parameter based on the output signal from the sound input device, allowing the system to adapt to fluctuating environmental conditions and maintain accurate noise cancellation across different operating scenarios.
Solution Approach 2:
The patent implements feedback by using the output signal from the sound input device to adjust the update parameter. This closed-loop mechanism allows the system to continuously monitor noise characteristics and modify the filter coefficient update process accordingly, improving noise cancellation accuracy under varying environmental conditions.
Data Source
AI summary
A signal processing device includes a coefficient updater configured to calculate a filter coefficient based on a reference signal, an error signal, and an update parameter to set the filter coefficient in a noise cancelling filter. A parameter adjuster adjusts the update parameter according to fluctuation of the reference signal produced from an output of a reference microphone.