Multipath ADC Path Matching for Smooth Signal Switching
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Solution Overview
Problem
Existing multipath ADC/AFE systems face challenges in smooth switching between paths, leading to signal artifacts and poor scalability to integrated circuit levels, which affects noise reduction and dynamic range in audio applications.
Innovation Solution
A signal processing system with multiple paths and an adaptive filter or linear correction subsystem that adjusts responses to minimize differences between digital signals generated by each path, and a controller that selects the appropriate path based on signal magnitude to reduce nonlinearities and artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching is implemented between multiple processing paths, then dynamic range and noise reduction are improved, but signal artifacts occur due to non-smooth transitions
Solution Approach 1:
The patent employs feedback mechanisms where the output of one processing path is used to adjust and correct the other path. Specifically, the first digital signal from the low-noise path is used to correct nonlinearities in the second digital signal from the high-dynamic-range path, enabling smooth transitions without artifacts. This cross-path feedback ensures continuous, artifact-free signal processing during path switching.
Solution Approach 2:
The patent introduces an intermediary correction mechanism that mediates between the two processing paths. A correction signal is generated by comparing outputs from both paths and is applied as an intermediate adjustment to ensure smooth transitions. This intermediary element acts as a buffer that prevents direct, abrupt switching artifacts while maintaining the benefits of both paths.
2Reliability
If multiple separate AFE/ADC paths are used, then noise reduction and dynamic range are improved, but device complexity and area increase
Solution Approach 1:
The patent merges the functionality of multiple processing paths into a unified system where both low-noise and high-dynamic-range processing occur simultaneously in parallel paths. The outputs of both paths are combined through correction mechanisms to produce a single optimized digital output. This merging approach maintains the noise reduction benefits of separate paths while reducing overall system complexity through integrated processing and shared correction logic.
3Adaptability or versatility
If path switching is implemented, then dynamic range is improved, but switching smoothness deteriorates leading to artifacts
Solution Approach 1:
The patent ensures continuity of useful action by maintaining both processing paths active simultaneously rather than switching between them. The low-noise path and high-dynamic-range path operate in parallel, with their outputs continuously combined through correction mechanisms. This continuous operation of both paths eliminates discontinuities and artifacts associated with switching, while still providing the full dynamic range and noise reduction benefits.
Data Source
AI summary
A method may include processing an analog input signal with a first processing path configured to generate a first digital signal based on the analog input signal; processing the analog input signal with a second processing path configured to generate a second digital signal based on the analog input signal, and adapting a response of an adaptive filter configured to generate a filtered digital signal from the second digital signal to reduce a difference between the filtered digital signal and the first digital signal. The method may additionally or alternatively include determining nonlinearities present in the second processing path based on comparison of the first digital signal and the second digital signal, and applying a linear correction to the second digital signal to generate a corrected second digital signal with decreased nonlinearity from that of the second digital signal.