Active Noise Reducing Device Combined Reference Signal Generation
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Solution Overview
Problem
Conventional active noise reducing devices require a large number of adaptive filters when using multiple reference signals, leading to increased arithmetic operations and complexity.
Innovation Solution
The device employs a combined reference signal generation unit that uses multiple filters to generate a single combined reference signal, reducing the number of adaptive filters needed by applying filters with non-overlapping passbands to the reference signals, thereby attenuating unnecessary bands and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple reference signals are used in conventional active noise reducing devices, then noise reduction performance is improved, but the number of adaptive filters increases leading to increased arithmetic operations and device complexity
Solution Approach 1:
The patent combines multiple reference signals into a single composite reference signal by applying filters with non-overlapping passbands to each reference signal and then summing them. This merging approach allows the system to use multiple reference signals for improved noise reduction performance while requiring only one adaptive filter, thereby reducing device complexity and arithmetic operations compared to conventional approaches that would require separate adaptive filters for each reference signal
Solution Approach 2:
The patent segments the frequency spectrum by applying filters with non-overlapping passbands to different reference signals. Each filter processes a specific frequency band, and the filtered signals are then combined. This segmentation allows efficient utilization of multiple reference signals while maintaining a single adaptive filter structure, resolving the contradiction between performance and complexity
2Reliability
If multiple adaptive filters are used to process multiple reference signals, then noise reduction performance is improved, but arithmetic operations increase
Solution Approach 1:
The patent merges multiple reference signal processing paths into a single adaptive filter by combining the filtered reference signals before the adaptive filtering stage. This approach maintains the benefits of multiple reference signals for noise reduction performance while significantly reducing the number of arithmetic operations required, as one adaptive filter processes the combined signal rather than multiple adaptive filters processing individual signals
Data Source
AI summary
A combined reference signal generation unit included in an active noise reducing device has a plurality of filters that is applied on a one-on-one basis to the plurality of input reference signals and an adder that adds up the plurality of reference signals to which the plurality of filters is applied on a one-on-one basis to generate a combined reference signal.