Vibration Rectification Error Correction via Timing Control
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Solution Overview
Problem
Existing sensor modules face challenges in correcting vibration rectification errors caused by non-linearity in low-pass filters, which affects the accuracy of physical quantity measurements.
Innovation Solution
A vibration rectification error correction device that includes a reference signal generation circuit, a frequency delta-sigma modulation circuit, filters, and a timing control circuit, which performs frequency delta-sigma modulation, filtering, and timing control to synchronize and correct the vibration rectification errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the group delay amount of the first low-pass filter is adjusted to correct vibration rectification error, then the vibration rectification error is reduced, but the group delay amount changes according to sensor characteristics requiring individual adjustment
Solution Approach 1:
The patent changes the parameter being adjusted from group delay amount to output timing of the measured signal. By adjusting when the measured signal is output relative to the reference signal timing, the vibration rectification error is corrected without changing the filter's internal group delay characteristics. This allows a single standard design to work across different sensor types.
Solution Approach 2:
Instead of adjusting the filter's group delay to achieve timing synchronization (the conventional approach), the patent inverts the approach by keeping the filter fixed and adjusting the output timing of the measured signal. This inversion simplifies the system by eliminating the need for variable group delay adjustment mechanisms.
2Measurement precision
If frequency delta-sigma modulation is performed on reference signal using measured signal, then vibration rectification errors are synchronized and corrected, but the device complexity increases with multiple circuits
Solution Approach 1:
The frequency delta-sigma modulation circuit performs multiple functions: it modulates the reference signal with the measured signal to generate timing information, and also serves as part of the overall signal processing chain. This multi-functionality reduces the need for separate dedicated circuits for each function.
Solution Approach 2:
The patent merges the timing control function with the frequency delta-sigma modulation process. The modulation process itself generates the timing relationship between reference and measured signals, eliminating the need for separate timing generation circuits and reducing overall system complexity.
Data Source
AI summary
A vibration rectification error correction device includes a reference signal generation circuit that outputs a reference signal, a first frequency delta-sigma modulation circuit that performs frequency delta-sigma modulation on the reference signal by using a first measured signal to generate a first frequency delta-sigma modulated signal, a first filter, a second filter that operates in synchronization with the reference signal, and a first timing control circuit that controls a timing of outputting an input signal in synchronization with the first timing signal, in which the first filter and the first timing control circuit are provided on a signal path from an output of the first frequency delta-sigma modulation circuit to an input of the second filter.