Resonant Frequency Sensor Module for Nonlinearity Correction
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Solution Overview
Problem
Physical quantity sensors, such as those detecting acceleration, face nonlinearity issues in their output values, which are not linearly related to the detected physical quantity, leading to increased circuit complexity and cost when traditional nonlinearity correction circuits are employed.
Innovation Solution
A physical quantity sensor module incorporating a resonant frequency shift sensor, a reference signal oscillator, and a frequency delta-sigma modulator, along with filters, corrects nonlinearity without the need for a dedicated correction circuit by using a combination of filters that operate synchronously with the measurement and reference signals, reducing noise and vibration rectification errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a nonlinearity correction circuit is provided to correct the nonlinearity of the physical quantity sensor output, then the measurement precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent combines the nonlinearity correction function with the existing output amplification circuit by setting the correction coefficient based on the output signal level. This merging approach allows the same circuit to perform both amplification and nonlinearity correction, eliminating the need for a separate dedicated correction circuit and reducing overall device complexity while maintaining measurement precision
Solution Approach 2:
The patent changes the amplification parameter dynamically based on the output signal level to correct nonlinearity. By adjusting the correction coefficient according to different signal levels, the system achieves nonlinearity correction without requiring complex additional circuits, thus improving measurement precision while controlling device complexity
2Measurement precision
If a nonlinearity correction circuit is provided to correct the nonlinearity of the physical quantity sensor output, then the measurement precision is improved, but the manufacturing cost increases
Solution Approach 1:
The patent merges the nonlinearity correction function into the existing output amplification circuit, allowing a single circuit to perform both amplification and correction. This integration reduces the total component count and circuit complexity, thereby lowering manufacturing costs while maintaining improved measurement precision through nonlinearity correction
Solution Approach 2:
The patent makes the output amplification circuit universal by enabling it to perform both amplification and nonlinearity correction functions. This multi-functionality approach eliminates the need for separate dedicated correction circuits, reducing manufacturing complexity and cost while achieving the desired measurement precision improvement
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 nonlinearity correction in physical quantity sensors without increasing the sensor module's size or cost, achieving higher accuracy in inclination and attitude calculations for applications like clinometers and inertial measurement devices.
Implementation Method 1
a resonant frequency shift based physical quantity sensor whose frequency adjusts with a adjust in physical quantity
Implementation Method 2
a frequency delta-sigma modulator which performs frequency delta-sigma modulation of a reference signal, using an operation signal based on a measurement target signal
Data Source
AI summary
A physical quantity sensor module includes: a resonant frequency shift based physical quantity sensor whose frequency adjusts with a adjust in physical quantity; a reference signal oscillator which outputs a reference signal; a frequency delta-sigma modulator which performs frequency delta-sigma modulation of the reference signal, using an operation signal based on a measurement target signal as an output from the resonant frequency shift based physical quantity sensor, and generates a frequency delta-sigma modulated signal; a first low-pass filter provided on an output side of the frequency delta-sigma modulator and operating synchronously with the measurement target signal as the output from the resonant frequency shift based physical quantity sensor; and a second low-pass filter provided on an output side of the first low-pass filter and operating synchronously with the reference signal.