Magnetic Field Detection System with Programmable Stimulus
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Solution Overview
Problem
Existing magnetic field detection techniques face challenges in accurately detecting very weak magnetic fields due to ambient environment changes, sampling jitter, and nonlinear effects, leading to high signal variation and errors, especially in applications like air mice and gyroscopes.
Innovation Solution
A magnetic field detection system comprising a magnetic impedance element surrounded by a detection coil, a stimulus unit generating programmable rise/fall signals, and a signal detection module with adjustable bandwidth, signal amplification, and digital signal processing to optimize detection results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual regulation of output voltage is used to compensate for Vso changes, then the circuit complexity is reduced, but the measurement precision deteriorates due to inability to accurately track environmental changes
Solution Approach 1:
The patent replaces manual mechanical regulation with an automated digital control system. A microcontroller automatically adjusts the output voltage of the operational amplifier by digitally controlling a variable resistor, eliminating the need for manual intervention while maintaining high measurement precision through automated environmental compensation
Solution Approach 2:
The system implements self-service through automatic environmental compensation. The microcontroller continuously monitors environmental conditions and automatically adjusts circuit parameters to compensate for Vso changes, enabling the system to self-correct without external intervention and maintain accurate magnetic field detection
2Device complexity
If peak detection method is used to extract magnetic field signal, then the signal processing is simplified, but the measurement precision deteriorates due to sampling jitter at sharp peak tops
Solution Approach 1:
The patent applies dynamic signal processing by using a moving average filter that adapts to the signal characteristics. Instead of static peak detection, the system dynamically calculates the average signal over multiple sampling points, automatically adjusting to signal variations and eliminating sensitivity to sampling jitter while maintaining processing efficiency
Solution Approach 2:
The patent introduces a moving average filter as an intermediary between the raw signal and the final detection result. This intermediary processing step smooths out sampling jitter effects while preserving the underlying magnetic field signal, acting as a buffer that reduces noise without requiring complex processing
3Measurement precision
If high frequency current is applied to MI element for magnetic field detection, then the detection sensitivity is improved, but the reliability deteriorates due to nonlinear effects and element intrinsic noise
Solution Approach 1:
The patent implements feedback mechanisms where the system continuously monitors the output signal and automatically adjusts the excitation current parameters. When nonlinear effects or noise are detected, the microcontroller adjusts the frequency and amplitude of the excitation signal to optimize the operating point, maintaining high sensitivity while compensating for reliability issues through real-time feedback control
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the frequency and amplitude of the excitation current based on environmental conditions and signal quality. The system can switch between different frequency ranges and current levels to optimize the balance between sensitivity and reliability, selecting optimal parameters for different operating conditions
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 system provides high sensitivity and accuracy in detecting weak magnetic fields by reducing signal variation and noise, enhancing flexibility and reliability for applications requiring precise magnetic field detection.
Implementation Method 1
magnetic impedance element whose impedance changes according to an external magnetic field
Implementation Method 2
detecting the voltage signal generated by the detection coil wound around or arranged in the vicinity of the magnetic element
Data Source
AI summary
A system of detecting magnetic field comprises a magnetic impedance element surrounded by a detection coil, a stimulus unit that generates pulse signal of programmable rise/fall time to drive the magnetic impedance element, and a signal detection module that detects signal on the detection coil, wherein the signal detection module includes a buffer unit having adjustable bandwidth for shaping output signal of the detection coil, a signal amplify unit that includes a sample and hold circuit and a chopping programmable gain amplifier to amplify buffered signal from the buffer unit, a signal processing unit that processes amplified signal from the signal amplify unit by applying a selectable algorithm to output detection result, and a control unit that connects the signal processing unit to generate control parameters of the stimulus unit, the buffer unit, the signal amplify unit, and the signal processing unit.