Automatic Gain Control for Differential Transformer Signal Stability
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Solution Overview
Problem
Existing automatic gain control (AGC) systems for differential transformers, such as LVDTs and RVDTs, face challenges in accurately and efficiently adjusting gain due to complex non-linear operations in the analog domain, which are prone to inaccuracies from process variations and temperature drifts, leading to increased circuit complexity and area requirements.
Innovation Solution
An apparatus and method for AGC that employs a sinewave generator module and gain control signal generator module to generate an approximated sinusoidal function based on linear operations in the analog domain, using multiplexing and filtering techniques to determine the amplitude of input signals, thereby reducing complexity and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If complex non-linear operations are used in the analog domain for gain control, then the gain adjustment capability is improved, but the circuit complexity and area requirements increase
Solution Approach 1:
The patent replaces complex analog non-linear operations with digital signal processing. The analog domain operations are substituted with digital algorithms that compute gain adjustments based on signal amplitude detection, thereby reducing circuit complexity while maintaining gain control functionality.
Solution Approach 2:
The patent introduces an intermediary amplitude detection stage that measures signal amplitude and uses this information to control gain adjustment. This intermediary approach simplifies the direct non-linear operations by breaking them into measurable components that can be processed more simply.
2Ease of operation
If complex non-linear operations are used in the analog domain for gain control, then the gain adjustment capability is improved, but the circuit area requirements increase
Solution Approach 1:
The patent substitutes analog non-linear circuit operations with digital processing, which requires less physical circuit area. The digital implementation of amplitude detection and gain control reduces the overall circuit footprint compared to traditional analog approaches.
Solution Approach 2:
The patent employs universal digital processing blocks that can perform multiple functions including amplitude detection, gain calculation, and control signal generation. This multi-functionality reduces the total circuit area by eliminating the need for separate dedicated circuits for each function.
3Speed
If analog domain operations are used for determining amplitude, then the processing speed is improved, but the accuracy decreases due to process variations and temperature drifts
Solution Approach 1:
The patent replaces analog amplitude determination with digital signal processing. Digital operations are inherently more resistant to process variations and temperature drifts, thereby improving measurement accuracy while maintaining processing speed through efficient digital algorithms.
Solution Approach 2:
The patent implements feedback mechanisms where the digitally determined amplitude information is used to adjust gain control. This feedback loop ensures accurate amplitude measurement by continuously monitoring and correcting for variations, thereby improving precision without sacrificing processing speed.
Data Source
AI summary
Apparatus and methods for gain control of a circuit for measuring a parameter are provided. The apparatus includes a sinewave generator module and a gain control signal generator module. The sinewave generator module is configured to receive a first signal and a second signal. The first signal is proportional to a sinusoid of a measured parameter and the second signal corresponds to the first signal shifted by a quarter of a period of the sinusoid. The sinewave generator module is further configured to generate an approximated sinusoidal function over time by determining values of a shifted sine function with a first frequency at a plurality of sampling points. A phase shift and an amplitude of the shifted sine function are based on the first signal and second signal.