Hybrid Sensor Feedback Loop for Bandwidth and Precision
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Solution Overview
Problem
Existing closed-loop sensing systems face challenges in achieving high bandwidth, high dynamic range, and high precision due to limitations in analog feedback loops, such as offset voltages and demodulator imperfections, while digital feedback loops offer high precision but lower dynamic range, and high-resolution digital-to-analog converters are limited by lower bandwidth.
Innovation Solution
The method involves demodulating a sense signal using both analog and digital demodulators, determining the difference between their outputs, and integrating it to generate a feedback control signal, allowing for high-resolution digital corrections to cancel out analog errors, and using techniques like dithering with random noise to enhance DAC resolution without impacting bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If analog feedback loops are used, then high bandwidth and dynamic range are achieved, but precision is limited due to analog errors
Solution Approach 1:
The patent combines analog and digital feedback loops into a hybrid architecture where the analog loop handles high-bandwidth signals while the digital loop provides precision correction. The analog demodulator processes the sense signal at high speed, and the digital demodulator corrects precision errors by comparing its output with the analog demodulator output, thereby achieving both high bandwidth and high precision simultaneously.
2Measurement precision
If digital feedback loops are used, then high precision is achieved, but dynamic range is reduced
Solution Approach 1:
The hybrid feedback loop merges the strengths of both analog and digital systems. The analog demodulator preserves dynamic range by processing signals in the analog domain, while the digital demodulator enhances precision through accurate accumulation and error correction. The combined output achieves both high precision and wide dynamic range.
3Measurement precision
If high resolution digital to analog converters are used, then precision is improved, but bandwidth is reduced
Solution Approach 1:
The feedback control signal is segmented into two components: a high-bandwidth analog component from the analog demodulator and a high-precision digital component from the digital demodulator. This segmentation allows the system to achieve both high bandwidth and high resolution without requiring a single high-resolution DAC operating at high bandwidth.
Solution Approach 2:
The analog demodulator acts as an intermediary that processes the sense signal in the analog domain, preserving bandwidth. The digital demodulator then provides precision correction by comparing its output with the analog demodulator output. This intermediary approach avoids the bandwidth limitation of high-resolution DACs while maintaining both precision and bandwidth.
Data Source
AI summary
Improved methods and systems for feedback signals in a sensor system. An example method demodulates a sense signal using an analog demodulator and also demodulates the sinse signal using a digital demodulator. The difference between the result of the analog demodulator and the digital demodulator is determined and then integrated. A sensor feedback control signal is generated based on the integrated difference.