Signal Processing Apparatus for Ultrasonic Flow Meters
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Solution Overview
Problem
Existing ultrasonic flow meters face challenges in accurately measuring fluid flow rates due to limitations in signal processing technologies, which affect the precision and efficiency of measurements.
Innovation Solution
A signal processing apparatus is developed that includes a comparator with switchable threshold voltages and a controller to manage these voltages, allowing for accurate calculation of propagation times and flow rates by switching between zero cross, envelope, and error detection thresholds, and adjusting amplifier gain, thereby enhancing measurement accuracy and reducing size and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple separate comparators are used for zero cross detection, envelope detection, and error detection, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single comparator to perform multiple detection functions (zero cross detection, envelope detection, and error detection) through dynamic switching of reference voltages. The comparator's reference voltage input is controlled by a switch that connects to different reference voltage sources based on the current processing stage, allowing one component to replace what would traditionally require three separate comparators, thereby reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent implements dynamics by making the comparator's reference voltage adjustable and switchable in real-time during the signal processing sequence. The reference voltage transitions from zero cross threshold to envelope threshold to error detection threshold based on the processing stage, allowing the same hardware component to adapt its characteristics dynamically to meet different measurement requirements at different times.
2Measurement precision
If fixed gain amplification is used, then circuit simplicity is maintained, but signal processing accuracy deteriorates due to inability to adapt to varying signal conditions
Solution Approach 1:
The patent applies dynamics by implementing variable gain amplification where the amplifier's gain is adjusted based on the signal processing stage and detected signal characteristics. The gain control circuit receives control signals from the controller and modifies the amplifier's amplification factor dynamically, allowing optimal signal processing accuracy across different operating conditions while maintaining relatively simple circuit implementation.
Solution Approach 2:
The patent implements feedback by using the output from the comparator (which detects signal characteristics) to control the amplifier's gain setting. The controller monitors the comparator output and adjusts the amplifier gain accordingly, creating a feedback loop that automatically optimizes signal processing accuracy based on actual signal conditions without requiring complex manual calibration.
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 apparatus enables precise measurement of fluid flow rates by improving signal processing techniques, reducing power consumption, and minimizing errors in propagation time calculations, leading to more accurate and cost-effective flow rate determination.
Implementation Method 1
An ultrasonic flow meter may include a first ultrasonic sensor arranged on an upstream side where a fluid flows and a second ultrasonic sensor arranged on the downstream side
Implementation Method 2
The wedge causes the ultrasonic wave transmitted from the ultrasonic transceiver to enter the fluid at a desired angle
Implementation Method 3
the pipe propagating wave incident on the wedge is disturbed by the notch making it difficult to reach the ultrasonic transceiver. Therefore, the energy of the pipe propagating wave arriving at the ultrasonic transceiver is made smaller than the energy of the fluid propagating wave, thereby increasing an SN ratio
Data Source
AI summary
A signal processing apparatus for processing a signal is provided. The apparatus includes a comparator having one input terminal to which a signal is inputted, a first switch configured to switch between application and non-application of a reference voltage, a second switch configured to switch between application and non-application of an envelope reference voltage; a third switch configured to switch between application and non-application of an error detection reference voltage; and a controller configured to perform switching control of the first switch, the second switch and the third switch based on an output of the comparator.