Analog Filter Active Noise Control Audio Devices

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Solution Overview

Problem

Existing active noise control audio devices face challenges in responding quickly to environmental noise due to the large time delay caused by digital filter processing, which affects the noise reduction effect.

Innovation Solution

The use of an analog filter to adjust the gain and phase of the analog signal, reducing the need for digital-to-analog conversion and minimizing time delay, allowing for a timely noise reduction response.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a digital filter set is used to adjust gain and phase of the signal, then the noise reduction can be achieved, but the time delay increases resulting in slow response to environmental noises

Engineering Contradiction:

Improvenoise reduction effectVSAvoidtime delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the digital filter processing system with an analog filter system. The analog filter directly processes the analog signal from the microphone to generate the noise reduction sound, eliminating the need for digital-to-analog conversion and reducing processing time delay. This substitution of digital processing with analog processing resolves the contradiction between achieving noise reduction and minimizing time delay.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If digital-to-analog conversion is performed for signal processing, then the noise reduction can be implemented, but the signal conversion time increases affecting the response speed

Engineering Contradiction:

Improvenoise reduction capabilityVSAvoidresponse speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent eliminates the digital-to-analog conversion step by using an analog filter to process the analog signal directly. The analog filter receives the analog signal from the microphone and outputs the noise reduction sound directly to the speaker, bypassing the digital processing domain entirely. This removes the conversion time and improves response speed while maintaining noise reduction capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If multiple signal conversion steps are used in the processing chain, then the noise reduction function can be achieved, but the overall time delay increases

Engineering Contradiction:

Improvenoise reduction functionVSAvoidtotal processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent extracts and removes the unnecessary digital-to-analog conversion step from the signal processing chain. By using an analog filter instead of a digital filter, the patent eliminates the conversion steps while retaining the essential noise reduction function. This extraction of redundant conversion steps reduces the total processing time and improves the response speed of the noise reduction system.

Inventive Principle:

Principle #2Taking out (Extraction)

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

This approach enables the active noise control audio device to respond quickly to environmental noise, improving the noise reduction effect by reducing signal conversion and time delay.

Implementation Method 1

An analog filter is used to provide a gain for the first analog signal and to generate a second analog signal

Methodology Applied

Scientific EffectAnalog filtering: Filter (electronic)

Implementation Method 2

A speaker is used to generate a noise reduction sound

Methodology Applied

Scientific EffectElectroacoustic transduction:

Implementation Method 3

a microphone is used to collect an environmental noise and the noise reduction sound

Methodology Applied

Scientific EffectAcoustic transduction:

Implementation Method 4

the external environmental noise and the noise reduction sound offset with each other to achieve a noise elimination effect

Methodology Applied

Scientific EffectAcoustic interference: Interference

Data Source

PatentUS12322371B2Active noise control audio devices, methods, and storage media

Publication Date: 2025.06.03 SHENZHEN SHOKZ CO LTD

AI summary

The present disclosure provides an active noise control audio device, method and storage medium. The device includes: a speaker, a microphone, an analog filter, and a processing circuit. The speaker used to generate a noise reduction sound; the microphone used to collect an environmental noise and the noise reduction sound and generate a first analog signal; the analog filter used to provide a gain for the first analog signal and to generate a second analog signal, the second analog signal driving the speaker to generate the noise reduction sound; and the processing circuit used to send a control instruction to the analog filter to adjust the gain and a phase shift of the analog filter according to the first analog signal and the second analog signal.