Acoustic Flow Velocity Measurement Using Phase-Shifted Signals
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Solution Overview
Problem
Existing methods for determining physical and chemical properties of media using acoustic waves are cumbersome and costly due to complex signal processing requirements, particularly in determining flow velocity, which involves significant calculation effort and hardware costs.
Innovation Solution
The method employs two phase-shifted transmit signals of the same fundamental frequency to generate four receive signals, allowing for direct calculation of runtime differences and absolute runtimes without the need for expensive differential signal generation or digital signal processing, using a simplified formula to infer flow velocity and other properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex signal processing methods (cross correlation, Hilbert transform, Wavelett transforms) are used to determine runtime differences from receive signals, then measurement precision of flow velocity is improved, but device complexity and calculation effort increase significantly
Solution Approach 1:
The patent changes the parameter of transmit signal structure by using phase-shifted transmit signals (e.g., quadrature phase shift) instead of single transmit signals. This parameter change enables the extraction of runtime information through simpler algebraic operations on the received signals, avoiding complex signal processing while maintaining measurement precision
Solution Approach 2:
The patent applies preliminary action by pre-shifting the phase of transmit signals before transmission. This preliminary modification of the signal structure enables subsequent simplified processing, as the phase information is already encoded in a form that allows direct calculation of runtime differences without requiring cross correlation or Hilbert transforms
2Reliability
If multiple complex signal processing operations (cross correlation, Hilbert conversion) are performed to calculate phase relation and time difference, then reliability of flow velocity determination is improved, but productivity decreases due to considerable calculation effort
Solution Approach 1:
By changing the transmit signal parameter to phase-shifted signals, the patent transforms the problem from requiring complex temporal analysis to allowing direct algebraic extraction of runtime information. This parameter change maintains reliability while dramatically improving processing speed and productivity
Solution Approach 2:
The patent substitutes complex mechanical signal processing operations (cross correlation, Hilbert transform) with simpler mathematical operations (algebraic manipulation of phase-shifted signals). This replacement reduces calculation effort while maintaining the reliability of flow velocity determination
3Measurement precision
If expensive differential signal generation and digital signal processing hardware are used to determine runtime differences, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the signal generation parameter to use phase-shifted transmit signals, which enables runtime difference measurement through simpler hardware configurations. This reduces manufacturing costs by eliminating the need for expensive differential signal generation and complex digital signal processing hardware while maintaining measurement precision
Solution Approach 2:
The patent employs a simpler, more cost-effective signal processing approach that replaces expensive hardware components with less costly alternatives. The phase-shifted signal method allows using basic signal generators and simple processors instead of expensive differential signal generation equipment and complex digital signal processing hardware
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 reduces measurement uncertainty and calculation effort, achieving reliable and robust determination of flow velocity and other properties with minimal hardware usage, resulting in a more efficient and cost-effective process.
Implementation Method 1
at least two acoustic waves are generated by a transmit signal, which at least partly propagate through the medium along identical or different propagation directions
Implementation Method 2
The acoustic waves utilized for determining the properties for example are ultrasonic waves which are generated by a corresponding transmitter due to a transmit signal
Implementation Method 3
which each are received at a receiver located in the respective propagation direction. In a flowing medium, for example, acoustic waves on the one hand are generated in a first propagation direction in flow direction of the medium and on the other hand in a second propagation direction against the flow direction of the medium
Data Source
AI summary
A method for determining physical and/or chemical properties of a medium on the basis of at least one first and one second acoustic wave, which each have at least partly propagated through the medium from at least one transmitter to at least one receiver, is provided. From receive signals generated at least two receivers a runtime difference of the acoustic waves and/or an absolute runtime of an acoustic wave is determined and by means of a determined runtime difference and/or a determined absolute runtime physical and/or chemical properties of the medium are determined, such as for example a mean flow velocity.