Multi-Frequency Ultrasonic Interferometer for Substance Classification
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Solution Overview
Problem
Existing ultrasonic interferometers are limited in their ability to accurately measure travel time, density, and classification of substances due to their reliance on single frequency signals, inability to handle multiple frequencies simultaneously, and lack of scalability, leading to inefficiencies in monitoring fast processes and varying conditions.
Innovation Solution
A multi-frequency coded ultrasonic signal system that utilizes the natural higher harmonics of piezoceramic transducers to penetrate materials with small acoustic windows, allowing for simultaneous measurement of phase parameters and travel times across a range of frequencies, enabling accurate classification and dynamic monitoring of substances and processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single frequency ultrasonic signals are used, then the device complexity is reduced, but the measurement precision and classification accuracy deteriorate
Solution Approach 1:
The ultrasonic signal is segmented into multiple discrete frequency components (e.g., 5 frequencies spaced 50 kHz apart within a 200 kHz bandwidth). Each frequency component independently probes different aspects of the tissue medium, enabling precise measurement of travel times and classification of tissue state without requiring overly complex hardware
Solution Approach 2:
The system transitions from single-frequency measurement to multi-frequency measurement, adding the frequency dimension to the measurement space. This allows the system to capture frequency-dependent properties of tissue (dispersion, absorption) and achieve more accurate classification by analyzing how different frequency components propagate through the medium
2Productivity
If multiple frequencies are measured simultaneously, then the productivity and monitoring speed are improved, but the device complexity and signal processing requirements increase
Solution Approach 1:
Multiple frequency components are merged into a single broadband ultrasonic pulse signal. This combined signal is transmitted through the tissue medium simultaneously, and the reflected signal contains information from all frequency components. The system processes this single composite signal to extract travel times for all frequencies, achieving fast monitoring without requiring multiple separate transmission channels
Solution Approach 2:
The ultrasonic transducer and signal processing system are designed to handle multiple frequencies simultaneously. A single transducer configuration serves multiple measurement functions by analyzing different frequency components of the reflected signal, enabling the system to measure both fast and slow tissue processes without requiring separate specialized hardware for each frequency
3Device complexity
If phase-only measurement is used, then the device complexity is reduced, but the measurement precision deteriorates due to 360 degree phase shift ambiguity
Solution Approach 1:
The system measures not only the phase of the reflected ultrasonic signal but also its amplitude (magnitude). By combining phase and amplitude information, the system can disambiguate the 360-degree phase wraparound problem. The amplitude provides additional constraints that help determine the correct integer number of wavelength cycles in the travel time, enabling precise absolute travel time measurement rather than just phase difference
4Measurement precision
If individual sensor geometry and characteristics are used for measurements, then the measurement precision for that specific sensor is optimized, but the adaptability and scalability deteriorate as each system must relearn profiles
Solution Approach 1:
The system measures absolute travel times of ultrasonic signals through the tissue medium, which are physical quantities that are independent of the specific sensor's geometric characteristics or calibration. This universal measurement approach allows different sensor configurations (different sizes, shapes, positions) to all measure the same physical property (travel time), enabling profiles and classification models to be transferred between different sensor systems without relearning
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
Enables precise characterization and classification of substances by determining travel times and frequency-dependent properties, allowing for scalable, continuous monitoring and recognition of changes in materials and processes, even in closed containers or through thick tissues.
Implementation Method 1
A multi-frequency coded ultrasonic signal system that utilizes the natural higher harmonics of piezoceramic transducers
Implementation Method 2
simultaneous measurement of phase parameters and travel times across a range of frequencies
Data Source
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AI summary
An ultrasonic interferometer for the characterization of the matter (solids, fluids & gases) in a medium is described, along with a method of using the same. The interferometer accurately determines the travel time of the multi-frequency ultrasonic signal in the matter that is being queried. By carefully selecting the design of the multi-frequency ultrasound signal, various properties of the material can be derived using a trainable classification system to classify or recognise the substance, or state of a process. The apparatus exploits the normally undesirable higher harmonics characteristics of the piezoceramic transducer to gain penetration through a spatial-frequency window that is not suitable for the higher frequency signals that are required to achieve the measurements.