Integrated Microphone Module with Analog Signal Processing

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Solution Overview

Problem

Conventional microphone systems are bulky and power-intensive due to the need for separate DSP engines and JFET drivers, which limits their miniaturization and deployment in low-power applications, and they are susceptible to external interference.

Innovation Solution

An integrated acoustic processing module with ECM capsules directly connected to an analog signal processing circuit, encapsulated in a casing to shield from interference, eliminating the need for JFET drivers and employing analog processing to reduce size and power consumption, and incorporating non-volatile memory for configuration and acoustic profiles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If DSP engines and JFET drivers are used to improve sound quality and reduce interference, then audio processing capability and interference immunity are improved, but device size and power consumption increase

Engineering Contradiction:

Improveinterference immunityVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the JFET driver and analog signal processing circuitry into an integrated microphone module that is directly coupled to the ECM capsule. This integration eliminates the need for separate DSP engines while maintaining interference immunity through the low-impedance output stage, thereby reducing overall device size while preserving reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces complex digital signal processing systems with an analog low-impedance output stage that inherently provides interference immunity. By using analog circuitry with direct coupling to the ECM capsule, the system achieves reliable interference rejection without requiring bulky DSP engines, thus resolving the contradiction between reliability and device size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If DSP engines are used to improve sound quality, then noise reduction and directional sensitivity are improved, but power consumption increases

Engineering Contradiction:

Improvesound qualityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent substitutes digital signal processing with an analog low-impedance output stage that provides inherent noise reduction and interference rejection. This analog approach delivers improved sound quality through proper impedance matching and noise filtering while consuming significantly less power than digital DSP engines, thereby resolving the contradiction between sound quality and power consumption.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If JFET drivers are used to reduce output signal susceptibility to interference, then interference immunity is improved, but circuit area and power consumption increase

Engineering Contradiction:

Improveinterference immunityVSAvoidcircuit area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent merges the JFET driver circuitry directly with the ECM capsule to form an integrated microphone module. This integration maintains the low-impedance output capability that provides interference immunity while minimizing circuit area through close coupling and optimized layout, thereby resolving the contradiction between interference immunity and circuit area.

Inventive Principle:

Principle #5Merging (Combining)

4Adaptability or versatility

If separate IC chips with DSP engines are used to implement signal processing, then signal processing functionality is improved, but device size and complexity increase

Engineering Contradiction:

Improvesignal processing functionalityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent integrates signal processing functionality directly into the microphone module with the ECM capsule, eliminating the need for separate IC chips. This integration maintains signal processing capabilities while reducing device complexity through a unified design, thereby resolving the contradiction between adaptability and device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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 module achieves significant size and power reduction, improved sound quality through noise reduction and directional sensitivity, and immunity to external interference, making it suitable for miniaturized and low-power applications.

Implementation Method 1

an electret condenser microphone (ECM) converts acoustic signals (e.g., such as a person's voice) into analog electrical signals

Methodology Applied

Scientific EffectElectromagnetic transduction:

Implementation Method 2

JFET 52 amplifies the electrical signals received from ECM capsule 51 to produce a low-impedance analog output signal

Methodology Applied

Scientific EffectField-effect transistor amplification:

Implementation Method 3

A coupling capacitor (Cin) blocks unwanted DC components of the analog input signal from being transmitted to circuitry 510 within device 500

Methodology Applied

Scientific EffectCapacitive blocking: Capacitance

Data Source

PatentUS8059849B2Small-footprint microphone module with signal processing functionality

Publication Date: 2011.11.15 NAT ACQUISITION SUB

AI summary

An acoustic processing module receives an acoustic signal, and outputs an analog output signal. Microphone sensors are provided for generating a corresponding electrical signal in response to the acoustic signal. A signal processing circuit is connected to the microphone sensors, and processes the electrical signals according to one or more analog signal processing functions to generate the analog output signal. An integrated casing encapsulates the microphone sensors and the analog processing circuit, and prevents external interference from affecting any electrical signals within the integrated casing.