Magnetometer Readout Circuit for ADC Noise Reduction
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Solution Overview
Problem
Magnetometers face challenges in reducing noise power, particularly from analog-digital converters, which limits their performance due to inherent technology limitations and requires increased electrical power, leading to inefficiencies and higher power consumption.
Innovation Solution
The proposed magnetometer design includes a first and second amplifier device with a summation element to reduce the dynamic range of the input signal, followed by a low-pass filter and analog-digital converter, where the output signal is corrected using a digital correction factor to minimize noise power, allowing for greater amplification of the residual signal and reducing noise contributions from the analog-digital converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the dynamic range of the input signal is reduced through defined attenuation, then the residual signal can be amplified to a greater degree and noise power from the analog-digital converter is reduced, but the hardware complexity increases due to additional amplifier stages and correction elements
Solution Approach 1:
The first amplifier device is divided into two separate amplifier stages (first and second amplifier devices) with a summation element between them. This segmentation allows the dynamic range to be reduced at the summation element, enabling the second amplifier to provide greater amplification of the residual signal with reduced noise power from the analog-digital converter.
Solution Approach 2:
A correction element is introduced as an intermediary component that receives the output signal from the analog-digital converter and applies digital correction by dividing by a correction factor and adding a digital correction signal. This intermediary element compensates for the defined attenuation applied earlier in the signal path, maintaining signal accuracy while benefiting from reduced noise power.
2Object-affected harmful factors
If greater amplification is applied to the residual signal after dynamic range reduction, then noise power from the analog-digital converter is reduced, but the device requires more electrical power consumption
Solution Approach 1:
The dynamic range reduction is performed preliminarily through the summation element before the second amplifier stage. By reducing the dynamic range early in the signal path, the subsequent amplification stage can operate more efficiently with lower noise power, and the correction element performs digital correction rather than requiring additional analog amplification stages that would consume more power.
Data Source
AI summary
A magnetometer includes a measurement value transducer that supplies a signal to a first amplifier device; a summation element that reduces an output signal range of an output signal of the first amplifier device; a second amplifier device that amplifies an output signal of the summation element; a low-pass filter filtering an output signal of the second amplifier device; an analog-digital converter converting output of the filter into digital form; and a correction element that divides the digital signal by a correction factor that corresponds to the defined gain factor of the second amplifier device and adds a digital correction signal to the quotient to form a resulting signal, where a scope of the correction signal corresponds to the defined attenuation of the output signal of the first amplifier device.