Switchable RC Low-Pass Filter for Sensor Sync Stability
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Solution Overview
Problem
Existing sensor technologies face challenges in accurately determining sync points in time due to component tolerances, junction temperatures, fluctuations in supply voltage, and variations in sync pulse frequency and duration, especially at high data transmission rates.
Innovation Solution
A sensor equipped with a switchable RC low-pass filter, an evaluation unit, and a synchronization unit, which stabilizes the reference signal by switching between two modes of the RC low-pass filter, allowing for accurate determination of sync points in time regardless of data transmission rate or sync pulse characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed time constant RC low-pass filter is used to generate the reference signal, then the filter provides stable filtering, but time-related deviations (jitter) in determining sync points increase due to supply voltage fluctuations and component tolerances
Solution Approach 1:
The patent applies the dynamics principle by making the RC low-pass filter time constant adjustable rather than fixed. The filter switches between a first time constant during sync pulse reception and a second time constant during data transmission, allowing optimization of both sync point determination accuracy and data communication stability under different operating conditions.
Solution Approach 2:
The patent implements parameter changes by varying the time constant parameter of the RC low-pass filter based on operational mode. The evaluation unit adjusts the time constant from a first value to a second value (and vice versa) depending on whether sync pulses or data are being transmitted, thereby adapting the filtering characteristics to minimize jitter during sync point detection while maintaining stable reference signals during data communication.
2Stability of the object's composition
If a longer time constant is used in the RC low-pass filter, then the reference signal is more stable, but the response to sync pulses becomes slower, reducing sync point determination accuracy
Solution Approach 1:
The patent resolves this contradiction by dynamically switching the time constant based on the operational phase. During sync pulse reception, a shorter time constant is used to ensure rapid response and accurate sync point determination. During data transmission periods, a longer time constant is applied to maintain reference signal stability, thus optimizing both requirements at different times.
Solution Approach 2:
The patent employs periodic action by alternately switching between two time constant values in sync with the communication protocol structure. The evaluation unit periodically changes the time constant parameter - using the first time constant during sync pulse intervals and the second time constant during data transmission intervals - thereby achieving both fast response and stable filtering through rhythmic parameter adjustment.
3Measurement precision
If a shorter time constant is used in the RC low-pass filter, then the response to sync pulses is faster, but the reference signal becomes more sensitive to noise and less stable
Solution Approach 1:
The patent applies dynamics by making the time constant adjustable rather than fixed. A shorter time constant is used only during sync pulse reception to ensure fast response and accurate sync point determination, while a longer time constant is used during data transmission to provide stable filtering and reduce noise sensitivity, thus achieving both fast response and stability through temporal separation.
4Productivity
If high data transmission rates are used, then communication efficiency increases, but sync point determination becomes more difficult due to reduced time margins
Solution Approach 1:
The patent applies preliminary action by preparing the reference signal in advance with optimal filtering characteristics before sync pulses arrive. The evaluation unit switches to the first time constant mode in anticipation of sync pulse reception, ensuring the reference signal is already optimized for accurate sync point determination when the sync pulses arrive, thereby maintaining high data transmission rates without sacrificing sync detection accuracy.
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 solution reduces time-related deviations (jitter) in determining sync points, ensuring stable data communication across various data transmission rates and sync pulse configurations, thereby enhancing the flexibility and reliability of the sensor network.
Implementation Method 1
The switchable RC low-pass filter is set up to generate a reference signal by low-pass filtering an input signal of the RC low-pass filter, with a waveform of the input signal corresponding with a waveform of the supply voltage that is superimposed
Implementation Method 2
The switchable RC low-pass filter is furthermore set up to have a first time constant in a first mode of the RC low-pass filter and to have a second time constant in a second mode of the RC low-pass filter, the second time constant being shorter than the first time constant
Data Source
AI summary
A sensor and a sensor network. The sensor comprises a switchable RC low-pass filter, an evaluation unit, a synchronization unit, and a two-wire interface. The two-wire interface is configured to be connected to a control device to receive an electrical supply voltage, provided by the control device, for supplying the sensor with electrical energy, to receive sync pulses superimposed on the supply voltage for synchronizing a data transmission from the control device, and to transmit data to the control device. The RC low-pass filter generates a reference signal by low-pass filtering an input signal, and to have a first time constant in a first mode and a second time constant in a second mode, wherein the second time constant is shorter than the first time constant. The evaluation unit stabilizes the reference signal by alternately switching the RC low-pass filter into the first mode and into the second mode.