Sensor DC Offset Measurement via Feedback Modulation
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Solution Overview
Problem
Existing sensors face challenges in detecting and measuring DC offset changes during operational use, as the input signal cannot be de-coupled from physical parameters, making it difficult to adjust for offset compensation due to environmental stresses and changes in sensor properties.
Innovation Solution
A sensor circuit with a feedback mechanism that modulates the physical parameter of the sensor at a specific frequency, allowing for the separation of DC offset from the output signal without affecting the input signal, using a feedback circuit to generate a feedback signal that compensates for the DC offset by monitoring the sensor output in the frequency domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the input signal is de-coupled from physical parameters to measure DC offset, then DC offset measurement precision is improved, but the sensor cannot operate during measurement making it impractical for field use
Solution Approach 1:
The patent introduces a feedback signal as an intermediary that modulates the physical parameter (such as spring constant) without requiring decoupling of the input signal. This feedback signal acts as a mediator that enables DC offset measurement while the sensor remains operational, resolving the contradiction between measurement precision and ease of operation
Solution Approach 2:
The patent employs feedback by generating a feedback signal that is coupled to the sensor input to modulate the physical parameter. This feedback mechanism enables continuous DC offset measurement during sensor operation, allowing the system to maintain operational capability while achieving accurate offset detection through frequency-domain separation
2Difficulty of detecting and measuring
If the physical parameter is modulated to separate DC offset, then DC offset detection capability is improved, but the measurement signal may be affected by parameter modulation
Solution Approach 1:
The patent moves the DC offset detection problem to another dimension by using frequency domain separation. The physical parameter is modulated at a specific frequency, and the DC offset is detected by monitoring the output signal at that modulation frequency, separating the offset detection from the DC measurement dimension
Solution Approach 2:
The patent applies periodic action by modulating the physical parameter with a periodic feedback signal at a specific frequency. This periodic modulation creates a corresponding frequency component in the output signal that can be used to detect DC offset without affecting the DC measurement of the physical parameter
Data Source
AI summary
A sensor circuit enables detection of DC offset in a sensor output signal. The sensor circuit includes a sensor that generates a sensor output signal corresponding to a physical signal coupled to an input of the sensor, and a modulator that generates a modulation signal, the modulator being coupled to the sensor to modulate a physical parameter of the sensor and to enable a DC offset to be separated from the sensor output signal. To enable the circuit to measure the DC offset even though the sensor output signal is inversely proportional to the output signal, the circuit includes a feedback circuit configured to generate a feedback signal. The feedback signal is coupled to the input of the sensor to enable the physical parameter of the sensor to be modulated without modulating a portion of the sensor output signal attributable to the physical signal being converted to an electrical signal by the sensor.