Noise Reducing Device Dynamic Filter Switching
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Solution Overview
Problem
Conventional active noise reduction systems are unable to adapt to varying noise environments, as they are fixed with a single filter characteristic, leading to inadequate noise reduction in specific settings and difficulty in selecting the optimal filter characteristic for effective noise cancellation.
Innovation Solution
A noise reducing device with a sound collecting section, a noise reducing audio signal generating section, a switching section, and a control section that allows for switching between different noise reducing characteristics, enabling the generation of noise reducing audio signals based on predetermined characteristics, and an electric-to-acoustic converting section for reproducing sound, with a process off period for easy user evaluation of noise reduction effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fixed filter characteristic is used in the noise reducing system, then the device structure remains simple, but the noise reduction effectiveness deteriorates in specific noise environments
Solution Approach 1:
The patent implements dynamic switching between multiple filter characteristics based on detected noise environment. The system transitions from a static single filter to a dynamic multi-filter system that adapts its characteristics according to the surrounding noise conditions, thereby improving noise reduction effectiveness without permanently increasing structural complexity.
Solution Approach 2:
The patent changes the filter characteristic parameters by providing multiple preset filter characteristics with different frequency responses. The switching section selects appropriate filter parameters based on the noise environment detected by the microphone, allowing the system to optimize noise reduction for different acoustic conditions such as low-frequency dominant environments versus broadband noise environments.
2Adaptability or versatility
If multiple filter circuits with various characteristics are provided, then noise reduction adaptability improves, but device complexity increases
Solution Approach 1:
The system uses dynamic switching controlled by a microprocessor to select among multiple filter characteristics based on detected noise environments. This approach provides adaptability to different noise conditions while avoiding the permanent structural complexity of having all filters simultaneously active, as only one filter characteristic is active at a time.
Solution Approach 2:
The switching section and control unit serve multiple functions: they select appropriate filter characteristics, control the switching timing, and manage the overall adaptation process. This multi-functionality reduces the need for separate dedicated circuits for each filter characteristic, thereby managing device complexity while maintaining adaptability.
3Adaptability or versatility
If filter characteristic switching is performed during active noise reduction, then adaptability improves, but the ability to evaluate noise reduction effect deteriorates
Solution Approach 1:
The patent introduces periodic pauses in the noise reduction process at switching points, creating intervals where noise reduction is temporarily suspended. This periodic interruption allows users to hear the original noise without processing, enabling direct comparison and evaluation of the noise reduction effect when switching occurs, thereby maintaining ease of operation while improving adaptability.
Solution Approach 2:
The control unit predicts switching points in advance and suspends noise reduction processing before actual switching occurs. This preliminary suspension allows users to anticipate and evaluate the upcoming filter characteristic change, making the evaluation process more intuitive and maintaining user control over the adaptation process.
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
Enables effective noise reduction in various environments by allowing users to easily switch and evaluate noise reduction characteristics, ensuring optimal noise cancellation at all times.
Implementation Method 1
a sound collecting section for collecting sound and outputting a noise signal
Implementation Method 2
an electric-to-acoustic converting section for acoustically reproducing sound on a basis of the noise reducing audio signal
Data Source
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AI summary
Disclosed herein is a noise reducing device (20) comprising: a sound collecting section (21) for collecting sound and outputting a noise signal; a noise reducing audio signal generating section (23) for generating a noise reducing audio signal on the basis of said noise signal and a predetermined noise reducing characteristic; an electric-to-acoustic converting section (11) for acoustically reproducing sound on a basis of said noise reducing audio signal; a switching section (25) for switching the noise reducing characteristic from one noise reducing characteristic to another noise reducing characteristic; and a control section (2325) for controlling said switching such that the generation of said noise reducing audio signal is stopped for a predetermined period of time between the application of said one noise reducing characteristic and said another noise reducing characteristic.