Hysteresis-Tracking Offset Compensation for Low-Distortion Sensor Signals
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Solution Overview
Problem
Existing sensor apparatuses face challenges in removing offset components from sensor signals without distorting the interesting components, and the limited space for miniaturized electronic devices restricts the implementation of complex preprocessing devices to attenuate these distortions.
Innovation Solution
A filter device comprising energy storage elements connected via a switching circuit that generates artificial ohmic resistance, allowing for the omission of ohmic resistors and reducing the size of energy storage elements, along with a signal processor that generates a new output signal by verifying the filtered signal against the input signal to prevent distortions, using a low pass filter to accurately remove offset components without affecting other frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional filters combining energy storage elements and ohmic resistors are used to remove offset components, then the offset removal function is achieved, but the device occupies more space and becomes more complex
Solution Approach 1:
The patent extracts and removes the ohmic resistor from the conventional filter structure, retaining only the energy storage elements (capacitors). The switching circuit replaces the resistor's function of defining the time window, thereby simplifying the filter structure and reducing device occupancy while maintaining offset removal capability.
Solution Approach 2:
The patent substitutes the passive ohmic resistor with an active switching circuit that uses switching elements to control the connection between capacitors. This replacement achieves the same time window definition function but with reduced physical space and improved integration for miniaturized devices.
2Measurement precision
If conventional filters with ohmic resistors and energy storage elements are used, then offset components can be removed, but the implementation space increases
Solution Approach 1:
The patent removes the ohmic resistor from the filter structure entirely, keeping only the essential energy storage elements. The switching circuit assumes the functional role of the resistor in defining the analysis time window, thereby reducing the physical area required for filter implementation in miniaturized sensor devices.
Solution Approach 2:
The patent changes the operational parameters of the filter by using switching elements to dynamically control the connection states of capacitors. This allows the filter to achieve the desired time window and frequency response characteristics without requiring physical resistors, thus reducing implementation area.
3Measurement precision
If high pass filter is used to remove offset component, then offset removal is achieved, but the interesting signal components around 0 Hz are distorted
Solution Approach 1:
The patent uses a low pass filter instead of a high pass filter, changing the filtering approach. The low pass filter with appropriately selected time constant removes the offset component (DC signal) while preserving the interesting signal components around 0 Hz, thereby avoiding the distortion problem associated with high pass filters.
Solution Approach 2:
The patent employs periodic switching of the capacitors to create a moving average effect that selectively removes DC offset while preserving low-frequency signal components. This periodic action allows precise control over which frequency components are attenuated, preventing distortion of interesting signals.
4Measurement precision
If complex preprocessing devices are provided to attenuate distortions, then measurement accuracy is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent performs preliminary action by carefully designing the low pass filter parameters (time constant) to prevent distortion of interesting signal components in the first place. This proactive approach avoids the need for complex post-processing devices to correct distortions, thereby maintaining measurement accuracy while minimizing device complexity.
Solution Approach 2:
The patent converts the potential harm of offset removal (which could cause signal distortion) into a benefit by using a low pass filter approach that selectively removes only the DC offset while preserving low-frequency signal components. This approach turns a potentially harmful operation into a beneficial one that maintains signal integrity.
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 solution effectively reduces space requirements while providing an offset-free measurement signal with minimal distortion, improving the accuracy of sensor measurements and reducing the need for additional signal processing.
Implementation Method 1
Both storage elements are connected via a switching circuit, which is adapted to enable and disable a connection between the first and second storage element
Implementation Method 2
using a low pass filter to accurately remove offset components without affecting other frequency components
Implementation Method 3
a first energy storage element receiving the input signal and a second energy storage element outputting the filtered output signal
Data Source
AI summary
A signal processor for removing at least one unintended signal component from an input signal (ua) is proposed. The signal processor includes a filter device (130) and a processing device (150). The filter device (130) filters the input signal (uâ) and generates a filtered signal (uf), which includes the unintended signal component to be removed. The processing device (150) generates an output signal (um), which indicates a deviation of the input signal (ua) from the filtered input signal (uf). By detecting the unintended signal component first an removing this component from the input signal (uâ), the input signal will not be manipulated directly but the unintended signal component in the input signal (uâ) will be compensated. This allows to remove the unintended component from the input signal (uâ) with less distortions of the interesting components in the input signal (uâ).