Acoustic Time-of-Flight Measurement Using Electromagnetic Timing Reference
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Solution Overview
Problem
Achieving accurate time-of-flight measurements of acoustic signals in systems like ultrasonic level detectors and flow meters is challenging due to the need for precise timing reference, particularly in pitch-catch configurations, where communicating the electrical signal from the transmit device to the receive device is difficult and prone to delays.
Innovation Solution
The method involves transmitting both an electromagnetic wave and an acoustic signal coincidently, with the receive device detecting features of both signals to estimate the time-of-flight by calculating the difference between the reception times of the electromagnetic and acoustic signals, leveraging the faster speed of light for timing reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a copy of the electrical signal driving the acoustic transducer in the TX device is used for the receive device's reference, then the receive device can have a timing reference, but some means must be provided to communicate a sample of that electrical signal from the TX device to the RX device, increasing system complexity
Solution Approach 1:
The patent uses an electromagnetic wave as an intermediary carrier to transport timing information from the TX device to the RX device. Instead of directly communicating the electrical signal, the system modulates timing data onto an electromagnetic wave that naturally propagates through the medium, simplifying the communication infrastructure while maintaining measurement precision
Solution Approach 2:
The patent replaces the mechanical/electrical signal communication system with an electromagnetic field-based system. By using electromagnetic waves to carry timing reference information, the system eliminates the need for complex wired or wireless electrical signal transmission infrastructure between TX and RX devices
2Ease of operation
If a sample of the electrical signal driving the acoustic transducer is used, then the receive device can synchronize timing, but this does not reflect the delay in the acoustic transducer, reducing measurement accuracy
Solution Approach 1:
The patent applies preliminary action by pre-compensating for the acoustic transducer delay in the timing reference signal. Before using the electromagnetic wave to carry timing information, the system calculates and incorporates the known transducer delay characteristics, ensuring that the reference timing already accounts for this systematic error
Solution Approach 2:
The patent creates a corrected copy of the timing reference that explicitly excludes the acoustic transducer delay component. By separating and removing the transducer delay from the timing reference copy, the system provides a pure propagation time measurement that accurately reflects only the signal travel time through the medium
3Reliability
If the electrical signal communication method is used between TX and RX devices, then timing reference can be provided, but the system becomes more complex and less reliable
Solution Approach 1:
The electromagnetic wave serves as a reliable intermediary that naturally propagates without requiring complex communication infrastructure. This approach ensures timing reference availability while minimizing system complexity by leveraging the inherent properties of electromagnetic wave propagation
Solution Approach 2:
The electromagnetic wave performs multiple functions simultaneously: it carries timing reference information, provides synchronization between devices, and serves as a reliable communication medium without requiring separate dedicated communication channels, thereby reducing overall system complexity
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 provides an accurate and reliable method for estimating the time-of-flight of acoustic signals, improving measurement precision and overcoming previous limitations in pitch-catch systems by utilizing the electromagnetic wave for timing reference.
Implementation Method 1
transmitting both an electromagnetic wave and an acoustic signal from the transmit acoustic transducer
Implementation Method 2
receiving the electromagnetic wave at a receive acoustic transducer of a receive device
Implementation Method 3
receiving the acoustic signal at the receive acoustic transducer of the receive device
Data Source
AI summary
A method of estimating the time and flight of an acoustic signal transmitted by a transmit acoustic transducer determines a difference in time between receiving the transmitted acoustic signal and receiving an electromagnetic wave transmitted by the transmit acoustic transducer coincident with transmitting the acoustic signal.