Ultrasonic Flow Sensor Multi-Level Down Sampling
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Solution Overview
Problem
Existing flow sensors using ultrasonic waves for measuring flow rates in waterways and oceans face challenges with measurement time and resolution, particularly when flow rates are slow or fast, requiring high resolution and increased calculation time, and the Doppler technique's measurement range is limited by pulse repetition frequency.
Innovation Solution
A flow sensor and method that perform multiple level down sampling, adjusting sampling frequencies based on Doppler frequency comparisons with reference frequencies, allowing for improved accuracy and calculation speed by generating and comparing first and second digital signals, and determining output frequencies through fast Fourier transforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resolution is increased to measure flow rate with less error, then the measurement precision is improved, but the calculation time increases
Solution Approach 1:
The patent applies dynamic adjustment of sampling frequencies based on the estimated flow rate range. The sampling frequency is not fixed but adapts to the measurement conditions, switching between multiple predefined frequencies (e.g., 100 Hz, 50 Hz, 25 Hz) to optimize the balance between measurement precision and calculation time for different flow rates
Solution Approach 2:
The patent changes the sampling frequency parameter based on the flow rate magnitude. By selecting different sampling frequencies from a predefined set and adjusting the number of samples accordingly, the system achieves high resolution for slow flows and fast calculation for fast flows, resolving the contradiction between precision and time
2Adaptability or versatility
If the pulse repetition frequency is increased to improve measurement range, then the measurable speed range is improved, but the measurement distance becomes shorter
Solution Approach 1:
The system dynamically selects the appropriate pulse repetition frequency based on the estimated flow rate. For slow flows, a lower pulse repetition frequency is used to extend measurement distance, while for fast flows, a higher pulse repetition frequency is used to capture the speed accurately, thus adapting to different measurement scenarios
3Measurement precision
If the sampling frequency is increased to improve measurement precision, then the measurement precision is improved, but the calculation time increases
Solution Approach 1:
The patent dynamically adjusts the sampling frequency based on the flow rate magnitude. For slow flows requiring high precision, a lower sampling frequency is used. For fast flows where high precision is less critical, a higher sampling frequency is used to reduce calculation time, thus optimizing the precision-speed trade-off
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
The method enables accurate and efficient flow rate measurement across a wide range of flow rates with reduced calculation time and uniform error, improving the performance of flow sensors in waterways and oceans.
Implementation Method 1
receiving an ultrasonic signal reflected from a particle
Implementation Method 2
generating a first Doppler frequency based on the first and second digital signals
Data Source
AI summary
Disclosed is a method of operating a flow sensor according to an embodiment of the present disclosure, which includes receiving an ultrasonic signal reflected from a particle, generating first and second digital, generating a first Doppler frequency based on the first and second digital signals, a predetermined number of samples, and a first time period, comparing the first Doppler frequency with a second reference frequency, when the first Doppler frequency is less than a first reference frequency, down-sampling the predetermined number of samples to a first sampling frequency or a second sampling frequency, generating a second Doppler frequency based on the first and second digital signals, the number of down-sampled samples, and a second time period determining an output frequency based on the second Doppler frequency when the first Doppler frequency is less than a first reference frequency, and obtaining flow information of the particle based on the output frequency.