Acoustic Transducer Interface Dynamic Interval Expansion

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Solution Overview

Problem

Existing solutions for expanding the dynamic interval of acoustic transducer signals suffer from complexity, noise sensitivity, low configurability, and non-optimal signal-to-noise ratio, leading to artefacts during switching between channels.

Innovation Solution

An electronic interface that combines signals from two sensing structures with different dynamic intervals using an intensity signal and variable thresholds, along with a recombining engine for generating a reconstructed signal through weighted combinations, reducing artefacts and optimizing signal-to-noise ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If parallel signal processing paths with different amplification factors are used to expand dynamic interval, then the dynamic interval is increased, but the device complexity and sensitivity to noise and oscillations increase

Engineering Contradiction:

Improvedynamic intervalVSAvoidprocessing chain complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The acoustic transducer is divided into two separate sensing structures (first and second sensing structures) with different mechanical characteristics, each producing a sensing signal optimized for different sound pressure levels. This segmentation allows the system to handle both low and high SPL effectively without requiring complex processing of a single signal path.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching between different signal paths based on the intensity signal. The reconstructed signal generator dynamically selects or combines signals from different processing paths according to the current sound pressure level, enabling adaptive optimization across the full dynamic interval while maintaining manageable processing complexity.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple signal processing paths with different gain factors are implemented, then signals with low and high sound pressure levels are adapted, but artefacts occur during switching between channels

Engineering Contradiction:

Improvesignal level adaptationVSAvoidsignal continuity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

An intensity signal is continuously measured from the first sensing signal and fed back to control the switching and combination operations in the reconstructed signal generator. This feedback mechanism ensures smooth transitions between different signal paths by using the actual signal intensity to determine when and how to switch or combine paths, preventing artefacts during transitions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the operational parameters (gain factors, switching thresholds) based on the intensity signal. By adjusting the combination weights and switching points according to the measured intensity, the system maintains signal continuity and avoids artefacts while adapting to different sound pressure levels.

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If equalization operations are performed to correct gain, offset, and phase differences, then signal distortion is prevented, but the processing complexity and sensitivity to noise increase

Engineering Contradiction:

Improvesignal equalization accuracyVSAvoidnoise sensitivity

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The sensing structures are designed with predetermined mechanical characteristics that inherently produce signals with appropriate gain, offset, and phase characteristics for their respective operating ranges. This preliminary design approach reduces the need for complex post-processing equalization operations, thereby lowering noise sensitivity while maintaining signal accuracy.

Inventive Principle:

Principle #10Preliminary action

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 solution effectively expands the dynamic interval of acoustic signals, reduces artefacts like clicks and pops, and ensures smooth switching, maintaining high sensitivity and signal quality across a wide range of sound pressure levels.

Implementation Method 1

acoustic transducer having two detection structures... configured to transduce acoustic pressure waves into an electrical quantity

Methodology Applied

Scientific EffectAcoustic transduction:

Implementation Method 2

The mobile electrode is generally anchored, through a perimetral portion, to a substrate, while a central portion thereof is free to move or bend in response to the pressure exerted by incident acoustic pressure waves and thus to modify the capacitance of the sensing capacitor

Methodology Applied

Scientific EffectCapacitance variation: Capacitance

Data Source

PatentUS9565506B2Interface for expanding the dynamic interval of an input signal of an acoustic transducer

Publication Date: 2017.02.07 STMICROELECTRONICS INT NV

AI summary

An interface for expanding a signal starting from a first sensing signal and a second sensing signal, wherein a receiving intensity measuring element generates an intensity signal; and a selector is controlled to select each time the first sensing signal, the second sensing signal, or a combined signal deriving from a weighted combination of these signals. The selector uses a plurality of thresholds variable as a function of the intensity signal.