Adaptive Low-Pass Filter for Fluid Compound Measurement
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Solution Overview
Problem
Existing devices for measuring and monitoring the concentration of components in fluids face a compromise between low-pass filtering efficiency and latency, where noise reduction introduces latency that can be detrimental in applications requiring rapid detection of dangerous or vital changes.
Innovation Solution
A device with a signal processing module that dynamically adjusts the high cut-off frequency of the low-pass filter based on the instantaneous trend of the signal within a predetermined sliding time window, using methods such as linear regression or fuzzy logic, to balance noise reduction and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a low-pass filter is applied to the quantitative tracking signal to remove noise and smooth the signal, then the signal clarity and ease of interpretation are improved, but the latency between the estimated quantity or concentration and the actual quantity or concentration increases
Solution Approach 1:
The patent applies dynamics by making the low-pass filter adaptive rather than static. The filter continuously adjusts its characteristics based on the instantaneous trend of the signal, allowing it to respond dynamically to changing conditions. This enables the system to maintain optimal signal clarity while minimizing latency by reducing filtering strength when rapid changes occur.
Solution Approach 2:
The patent changes the parameter of the low-pass filter (its cutoff frequency or filtering strength) based on the signal's instantaneous trend. When the signal shows rapid variation, the filter parameter is adjusted to reduce latency; when the signal is stable, the parameter is adjusted to maximize noise reduction. This parameter adaptation resolves the contradiction between signal clarity and latency.
2Reliability
If a fixed low-pass filter with optimized parameters is used, then a compromise between noise reduction and latency is achieved, but the system cannot respond optimally to rapid changes in component concentration
Solution Approach 1:
The patent implements feedback by using the instantaneous trend of the signal to control the low-pass filter parameters. The system continuously monitors the signal's rate of change and uses this information to adjust the filtering strength, creating a closed-loop control system. This feedback mechanism enables the system to adapt to rapid changes while maintaining reliability in normal operating conditions.
Solution Approach 2:
The system transitions from a static filter configuration to a dynamic one where the filter characteristics change in real-time based on signal conditions. This dynamic adaptation allows the system to maintain high detection accuracy during stable periods while becoming highly responsive during rapid changes, resolving the contradiction between reliability and adaptability.
3Loss of time
If the high cutoff frequency of the low-pass filter is increased to reduce latency, then the responsiveness to rapid changes is improved, but the signal becomes noisier and more difficult to interpret
Solution Approach 1:
The patent changes the cutoff frequency parameter of the low-pass filter dynamically based on the instantaneous trend of the signal. When rapid changes are detected, the cutoff frequency is increased to reduce latency; when the signal is stable, the cutoff frequency is decreased to maintain signal clarity. This parameter adaptation resolves the contradiction between latency and signal clarity.
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 allows for real-time adaptation of the filtering, effectively reducing latency while maintaining signal clarity, enabling prompt detection of rapid changes in fluid component concentrations without introducing excessive noise during stable or slow variations.
Implementation Method 1
optical detection methods based on the spectral absorption properties of the different species that can compose a gas and on Beer-Lambert's law
Implementation Method 2
a signal processing module including a low-pass filter for the quantitative tracking signal
Data Source
Figure 1~5
AI summary
Said device for measuring and tracking, over time, the quantity or concentration of a compound (C) in a fluid (F) comprises: a sensor (10) capable of measuring a quantity or concentration of the compound (C) in the fluid (F) and providing a quantitative signal for tracking said quantity or concentration over time; a signal processing module (12) having a low-pass filter (30) of the quantitative tracking signal; an output interface (36) for providing the filtered quantitative tracking signal. The signal processing module (12) comprises an estimator (32) of an instantaneous trend value of variation of the quantitative tracking signal in a predetermined sliding time window. It further comprises means (34) for adjusting, over time, a high cut-off frequency of the low-pass filter (30) according to the instantaneous trend value of the estimated variation.