Signal Processing Gain Correction With Compensation-Aware Scaling
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Solution Overview
Problem
Analog signal processing circuits, such as those used in photodetectors, face challenges in accurately resolving small signals due to gain errors and quantization noise from compensation voltages, leading to degraded signal-to-noise ratios and reduced resolution.
Innovation Solution
The method involves generating an offset compensation signal with a polarity opposite the gain error and a magnitude equal to a nominal value plus a deviation, which is applied to intermediate signals, and scaling the output based on the deviation and gain error coefficient to enhance resolution and reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offset compensation is applied to correct gain errors in signal processing circuitry, then gain accuracy is improved, but quantization noise from the compensation voltage degrades the signal-to-noise ratio
Solution Approach 1:
The patent introduces an intermediary scaling operation between the offset compensation application and the final output. A scaling factor is calculated based on the relationship between the actual compensation voltage and the ideal compensation voltage, and this scaling factor is applied to the output signal to remove the quantization noise introduced by the offset compensation process
Solution Approach 2:
The patent implements a feedback mechanism where the actual offset compensation voltage is monitored and compared against the ideal compensation voltage. Based on this comparison, a scaling factor is determined and applied to correct the output signal, creating a closed-loop system that eliminates quantization noise
2Adaptability or versatility
If the compensation voltage magnitude is increased to cover larger gain errors, then gain error correction range is improved, but the quantization noise magnitude increases
Solution Approach 1:
The patent changes the parameter of the compensation voltage to be variable rather than fixed. The compensation voltage magnitude is dynamically adjusted based on the actual gain error, and a corresponding scaling factor is applied to maintain optimal signal-to-noise ratio across different operating conditions
Data Source
AI summary
A method of processing an analog signal includes receiving, into signal processing circuitry from compensation circuitry, an offset compensation signal, the offset compensation signal having (i) a polarity opposite a polarity of a gain error of the signal processing circuitry and (ii) a magnitude equal to a nominal compensation value plus a deviation. The method includes generating, by the signal processing circuitry, an output signal based on an analog signal received into the signal processing circuitry, including applying the offset compensation signal to an intermediate signal generated by the signal processing circuitry. The method includes scaling the output signal based on the deviation between the magnitude of the offset compensation signal and the nominal compensation value.