Acoustic Transducer Loop Sensitivity Measurement via Pulse-Echo Energy Density

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Solution Overview

Problem

Existing methods for measuring acoustic transducer sensitivity are limited to single-frequency assessments, which are inadequate for wideband acoustic probes, and do not effectively capture the characteristic loop sensitivity of acoustic transducers.

Innovation Solution

A method and system that utilize a pulse generator to produce wideband reference and echo signals, calculating energy density ratios through Fourier Transforms to determine characteristic loop sensitivity (S LC ) across a range of frequencies, enabling the measurement of wideband characteristics of acoustic transducers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single specific frequency is used for measuring loop sensitivity, then the measurement method is simple, but it cannot capture the wideband characteristics of modern acoustic transducers

Engineering Contradiction:
Improvewideband measurement capabilityVSAvoidmeasurement system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the frequency parameter from a single specific value to a continuous range by using a pulse signal with broad spectral content. The pulse generator produces signals with frequencies spanning from DC to high frequencies, allowing measurement of the transducer's frequency response across its entire operating bandwidth rather than at a single point.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs periodic pulse signals as excitation instead of continuous sinusoidal waves. These pulses are applied in a periodic manner, and the resulting echo signals are analyzed using Fourier Transform to extract frequency-domain characteristics. This periodic pulsed action enables wideband measurement while maintaining a relatively simple time-domain measurement setup.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If traditional voltage ratio method is used, then the measurement is straightforward, but it does not accurately represent the energy characteristics of acoustic transducers

Engineering Contradiction:
Improvesensitivity measurement accuracyVSAvoidsignal processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the traditional direct voltage ratio measurement method with a signal processing approach using Fourier Transform. Instead of directly comparing voltages in the time domain, the method transforms both the reference and echo signals into the frequency domain, where the sensitivity is derived from the ratio of their spectral components. This substitution provides more accurate energy characterization.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces Fourier Transform as an intermediary processing step between signal acquisition and sensitivity calculation. The transform domain serves as an intermediate representation that reveals the frequency-dependent energy characteristics of the transducer, enabling more precise sensitivity measurement across different frequencies rather than a single averaged value.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 allows for the accurate assessment of wideband acoustic transducer sensitivity, providing a decibel-based ratio of energy density that effectively captures the performance of acoustic transducers in a pulse-echo mode, suitable for both unipolar and bipolar pulse signals.

Implementation Method 1

A pulse generator of 50-ohm source impedance... electrically couples to an acoustic probe... The acoustic probe is immersed into a water bath with an acoustic mirror. An acoustic transducer in the acoustic probe is driven by the pulse generator... and transmits a wideband acoustic wave

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

The acoustic probe is immersed into a water bath with an acoustic mirror 212. The acoustic probe 113 receives the reflected sine burst wave 218 from the acoustic mirror 212

Methodology Applied
Scientific EffectAcoustic reflection: Reflection

Implementation Method 3

An acoustic transducer in the acoustic probe is driven by the pulse generator... and transmits a wideband acoustic wave toward the acoustic mirror. The acoustic transducer receives the reflected wideband acoustic wave and outputs a wideband echo signal

Methodology Applied
Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Data Source

PatentEP3505927B1Method and system for measuring a characteristic loop sensitivity for an acoustic transducer
Publication Date: 2023.04.26 BROADSOUND
  • EP3505927B1 patent drawingFigure 1A~1B
  • EP3505927B1 patent drawingFigure 2A~2B
  • EP3505927B1 patent drawingFigure 3A~3B

AI summary

A method and system is disclosed for measuring a characteristic loop sensitivity (SLC) for an acoustic transducer. A pulse signal is employed as a wideband reference signal Vr(t); and, in a pulse-echo measurement a corresponding wideband echo signal Ve(t) is obtained. A characteristic loop sensitivity (SLC) for the acoustic transducer is defined as a ratio of an energy density of Ve(t) to an energy density of Vr(t) in decibel, in which the energy density of a given signal is calculated as a ratio of an energy of the signal to a bandwidth of the signal.