Rotary Encoder Signal Filtering for Adaptive Noise Rejection
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Solution Overview
Problem
Rotary encoders face challenges in enhancing their anti-noise performance, which directly impacts the quality and reliability of motor devices.
Innovation Solution
A signal processing device and method incorporating analog filters, analog-to-digital converters, digital filters, a dynamic offset calibration unit, a position detection unit, and a frequency generation module, which dynamically adjust filter bands based on frequency indication signals to reduce noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixed-band filtering is used in rotary encoders, then the device structure remains simple, but the anti-noise performance is insufficient and cannot adapt to varying noise conditions
Solution Approach 1:
The patent implements dynamic filter band adjustment by switching between different filter configurations based on detected signal frequency. The system transitions from static fixed-band filtering to dynamic adaptive filtering, where the filter characteristics change in real-time to match the operating conditions, thereby improving anti-noise performance without requiring overly complex fixed architecture
Solution Approach 2:
The patent changes the filter parameters (cut-off frequency, filter order) based on the detected frequency of the encoder signal. By adjusting these parameters dynamically, the system optimizes noise rejection for different operating speeds and conditions, resolving the contradiction between maintaining simplicity and achieving adaptive anti-noise performance
2Reliability
If multiple fixed filter bands are implemented to cover different frequencies, then the anti-noise performance improves, but the device complexity and number of components increase
Solution Approach 1:
The patent designs a universal filter structure that can operate in multiple modes (different filter orders and cut-off frequencies) by switching between predefined configurations. Instead of implementing separate dedicated filters for each frequency range, a single multi-functional filter unit handles all frequency conditions, reducing component count while maintaining comprehensive noise rejection capability
Solution Approach 2:
The system dynamically selects and switches between different filter configurations based on the detected signal frequency. This dynamic switching allows one filter structure to serve multiple frequency ranges, eliminating the need for multiple parallel fixed filters and thereby reducing overall device complexity while preserving broad anti-noise coverage
3Reliability
If dynamic filter adjustment is implemented to adapt to different frequencies, then the anti-noise performance improves, but the processing time and computational load increase
Solution Approach 1:
The patent pre-calculates and stores optimal filter parameters for different frequency ranges before operation. During real-time processing, the system only needs to detect the frequency range and switch to the pre-configured filter settings, rather than calculating optimal parameters from scratch. This preliminary preparation significantly reduces the computational time required during actual signal processing while maintaining adaptive anti-noise performance
Data Source
AI summary
An encoder and a signal processing method are disclosed. The method includes: receiving an analog signal, and generating a filtered analog signal by an analog filter according to the input signal and a first frequency indication signal; generating a digital signal by an analog-to-digital converter according to the filtered analog signal; generating a filtered digital signal by a digital filter according to the digital signal and a second frequency indication signal; generating a seventh signal and an eighth signal by a dynamic offset calibration unit according to the filtered digital signal and a period indication signal; and generating a position information by a position detection unit according to the seventh signal and the eighth signal. The first frequency indication signal, the second frequency indication signal and the period indication signal are generated by a frequency generation module according to the filtered analog signal or the digital signal.