Rotation Detection Apparatus Noise Immunity via Signal Binarization
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Solution Overview
Problem
Conventional rotation detection apparatuses for gear-shaped rotors with concavoconvex structures face errors due to insignificant midpoint potential changes, leading to incorrect binarized signal outputs from magnetoresistive element pairs, especially when scars or noise are present.
Innovation Solution
A rotation detection apparatus with a signal detector and determination circuit that generates and processes first and second signals based on the concavoconvex structure, using magnetoresistive element pairs and operational amplifiers to produce waveform signals, and applies a binarization threshold value to prevent erroneous outputs by controlling the output of binarized signals during specific periods corresponding to convexity and concavity phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the threshold value is set close to the midpoint potential of each magnetoresistive element pair to detect the concavoconvex structure, then the detection sensitivity is improved, but the system becomes susceptible to noise and scars causing erroneous binarized signal outputs
Solution Approach 1:
The patent combines the outputs of multiple magnetoresistive element pairs (first and second pairs) to generate two signals (first and second signals) that are then processed together. By merging multiple detection channels and requiring coordinated validation of both signals before generating a binarized output, the system achieves both high detection sensitivity and noise immunity, resolving the contradiction between measurement precision and reliability
Solution Approach 2:
The determination circuit continuously monitors both the first and second signals and uses feedback control to validate binarized signal generation. The circuit only outputs a binarized signal when both signals simultaneously satisfy their respective threshold conditions, providing feedback-based error prevention that maintains reliability while preserving detection sensitivity
2Measurement precision
If the threshold value is set close to the midpoint potential to detect insignificant changes, then the detection capability is improved, but noise and scars cause the threshold to be exceeded leading to erroneous outputs
Solution Approach 1:
The patent merges multiple detection channels by combining outputs from first and second magnetoresistive element pairs. The determination circuit requires both the first signal and second signal to simultaneously satisfy threshold conditions before generating a binarized output, thereby combining detection sensitivity with noise rejection capability
Solution Approach 2:
The determination circuit performs preliminary validation by checking both the first and second signals against their respective threshold conditions before allowing binarized signal generation. This preliminary action filters out noise and scar-induced errors that would otherwise cause erroneous outputs, while maintaining the ability to detect insignificant changes
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 prevents erroneous binarized signal outputs even when noise or scars are present, enhancing noise immunity and ensuring accurate detection of the rotor's rotation and concavoconvex structure.
Implementation Method 1
magnetoresistive element pairs whose respective resistance values change during the rotation of the rotor
Data Source
AI summary
A rotation detection apparatus includes a signal detector and a determination circuit. The signal detector outputs a first signal and a second signal based on changes in respective resistance values of magnetoresistive element pairs. The first signal has a waveform corresponding to convexities and concavities of a rotor, while the second signal has a waveform differing in phase from the first signal. Upon receiving the first signal and second signal, the determination circuit compares each of the first signal and second signal against a binarization threshold value to generate a first binarized signal and a second binarized signal. The determination circuit permits output of the first binarized signal during one of a concavity period and a convexity period of the second binarized signal, and prohibits output of the first binarized signal during the other one of the concavity period and convexity period.