Dual-Path ADC Nonlinearity Cancellation for Weak Signal Range
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Solution Overview
Problem
Conventional dual-path ADC systems face challenges in achieving high dynamic range without introducing noise and power consumption, particularly due to the need for amplifiers that increase noise and power usage.
Innovation Solution
A dual-path ADC system utilizing a VCO-based ADC for small-amplitude signals, employing non-linearity cancellation to remove nonlinearities, where a digital signal processing block determines and modifies non-linear coefficients to generate a more linear signal, and selects between two digital signals based on signal strength for further processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an amplifier is used to achieve high dynamic range for weak signals, then the dynamic range is improved, but noise and power consumption increase
Solution Approach 1:
Instead of amplifying weak signals before ADC conversion (conventional approach), the patent inverts the approach by using a VCO to convert weak analog signals directly to digital domain where they can be processed without analog amplification. This digital-first approach avoids the noise introduction inherent in analog amplification paths.
Solution Approach 2:
The patent replaces the analog amplifier (electrical/mechanical system) with a VCO-based digital conversion system. The VCO converts the analog input signal to a digital signal through frequency modulation, eliminating the need for noisy analog amplification stages while achieving the same dynamic range enhancement.
2Measurement precision
If an amplifier is used to achieve high dynamic range for weak signals, then the dynamic range is improved, but power consumption increases
Solution Approach 1:
The patent inverts the conventional signal processing approach by moving from analog amplification to digital conversion at the input stage. The VCO-based ADC converts weak analog signals to digital domain before further processing, eliminating the need for power-hungry analog amplifiers while maintaining dynamic range performance.
Solution Approach 2:
The patent substitutes the power-consuming analog amplifier with a VCO-based digital conversion system. The VCO operates at lower power by converting the signal to the digital domain through frequency modulation, eliminating the need for high-power analog amplification stages.
3Object-generated harmful factors
If a VCO-based ADC is used for small-amplitude signals, then noise and power consumption are reduced, but non-linearity is introduced
Solution Approach 1:
The patent extracts and separates the non-linear distortion components from the desired signal using digital signal processing. By identifying and removing the specific non-linear components introduced by the VCO, the system maintains the low-noise benefits while correcting the linearity issues through digital filtering and processing.
Solution Approach 2:
The patent employs digital feedback mechanisms to detect and correct non-linearities in the VCO-based ADC output. By monitoring the output signal and applying corrective digital processing, the system maintains high linearity while preserving the low-noise characteristics of the VCO approach.
Data Source
AI summary
The overall performance of a dual-path ADC system may be improved by using a VCO-based ADC for small-amplitude signals and employing non-linear cancelation to remove nonlinearities in signals output by the VCO-based ADC. In particular, VCO-based dual-path ADC systems of this disclosure may be configured to receive a first digital signal from a first ADC and a second digital signal from a second ADC, wherein the second digital signal is more non-linear than the first digital signal. The dual-path systems may also be configured to determine one or more non-linear coefficients of the second digital signal based, at least in part, on processing of the first and second digital signals. The dual-path systems may be further configured to modify the second digital signal based, at least in part, on the determined one or more non-linear coefficients to generate a more linear second digital signal.