CMUT Resonance Detection Using Broadband Ringdown Analysis
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Solution Overview
Problem
Existing capacitive micromachined ultrasound transducer (CMUT) systems face challenges in determining resonance frequency, which affects sensitivity in ultrasound otoscopy measurements, particularly due to manufacturing variations and environmental factors like altitude and directional orientation of the tympanic membrane.
Innovation Solution
A method involving a broadband electrical stimulus waveform is directed at the CMUT, followed by measuring its ringdown characteristic through Fourier transform to determine the resonance frequency, using a Doppler receiver for signal amplification and polynomial fitting to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed frequency stimulus is used for CMUT testing, then the measurement process is simple, but the sensitivity is reduced due to manufacturing variations and environmental factors causing resonance frequency shifts
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed frequency stimulus to a broadband stimulus that covers a range of frequencies. This allows the system to adapt to resonance frequency shifts caused by manufacturing variations and environmental factors, thereby improving measurement precision without requiring complex calibration procedures for each individual CMUT device.
Solution Approach 2:
The patent changes the frequency parameter from a single fixed value to a broadband spectrum. By using a stimulus waveform with bandwidth greater than the expected resonance frequency spread, the system can accurately determine the actual resonance frequency of each CMUT device, compensating for variations in manufacturing and environmental conditions.
2Measurement precision
If broadband electrical stimulus is used to determine resonance frequency, then measurement accuracy is improved, but the measurement and signal processing complexity increases
Solution Approach 1:
The patent utilizes mechanical vibration principles by analyzing the ringdown characteristic of the CMUT after broadband excitation. The ringdown signal contains the resonance frequency information, and by processing this vibrational response, the system can accurately determine the resonance frequency while using standard signal processing techniques like Fourier transform.
Solution Approach 2:
The patent introduces the ringdown characteristic as an intermediary that bridges the broadband stimulus and the resonance frequency determination. The ringdown signal serves as a mediator that contains the resonance information in a form that is easier to extract and analyze, simplifying the overall measurement and processing difficulty.
3Ease of operation
If resonance frequency is not accurately determined, then the system is simpler to operate, but the sensitivity and diagnostic accuracy of ultrasound otoscopy measurements deteriorates
Solution Approach 1:
The patent implements self-service by enabling the CMUT system to automatically determine its own resonance frequency through broadband stimulus and ringdown analysis. This self-determination process occurs without requiring external calibration equipment or complex manual procedures, maintaining ease of operation while ensuring accurate resonance frequency identification for reliable diagnostic measurements.
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 precise determination of CMUT resonance frequency, improving sensitivity and consistency of ultrasound otoscopy measurements by ensuring the transducer operates at its optimal frequency, thereby enhancing diagnostic accuracy.
Implementation Method 1
determining a resonance frequency of a capacitive micromachined ultrasound transducer... measuring a ringdown characteristic of the ultrasound transducer
Implementation Method 2
the ringdown characteristic of the ultrasound transducer is measured by a Doppler receiver configured to amplify the at least one emitted signal
Implementation Method 3
measuring the ringdown characteristic of the ultrasound transducer comprises calculating a Fourier transform of the amplified at least one emitted signal
Data Source
AI summary
A method of determining a resonance frequency of a capacitive micromachined ultrasound transducer may include directing a broadband excitation waveform at an ultrasound transducer, wherein the excitation waveform comprises a frequency band which includes an anticipated resonance frequency of the ultrasound transducer; and measuring a ringdown characteristic of the ultrasound transducer.