AFE Skew Compensation via Serial Data Serialization
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Solution Overview
Problem
Conventional multi-channel systems, such as bed scanners, experience skew due to manufacturing process variations in separate integrated circuits, leading to inconsistent input signals for processing units.
Innovation Solution
The implementation of a system with multiple analog front-end (AFE) units coupled in series, where each AFE unit outputs data packets simultaneously within a clock cycle, using a system clock signal and its integer multiples, to synchronize and compensate for skew between channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate integrated circuits are used for each AFE unit, then device complexity is reduced and manufacturing is easier, but skew between channels occurs due to manufacturing process variations
Solution Approach 1:
The patent applies preliminary action by measuring and characterizing the skew between different AFE units during manufacturing, then pre-calculating compensation values that are stored in lookup tables. During operation, the system retrieves pre-computed correction data based on measured skew characteristics, eliminating the need for real-time complex compensation calculations while maintaining signal accuracy across all channels.
2Productivity
If multiple AFE units operate independently with different clock phases, then each unit can process data at high speed, but skew occurs between the inputs to the processing unit
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual output timing of each AFE unit and comparing it against the ideal synchronized timing. Based on measured deviations, the system dynamically adjusts the phase of clock signals fed to each AFE unit, creating a closed-loop control system that maintains synchronized operation despite manufacturing variations and environmental conditions.
Solution Approach 2:
The patent changes the phase parameter of clock signals dynamically to compensate for skew. By adjusting the phase shift of clock inputs to different AFE units based on measured performance characteristics, the system optimizes timing alignment across all channels while maintaining high-speed operation. This is achieved through lookup tables that map phase adjustments to measured skew conditions.
3Manufacturing precision
If all AFE units are synchronized to output data packets simultaneously, then skew is eliminated, but the system complexity increases due to precise clock synchronization requirements
Solution Approach 1:
The patent reduces real-time synchronization complexity by pre-measuring and storing optimal phase relationships between clock signals for each AFE unit in lookup tables during manufacturing. During operation, the system simply retrieves pre-determined phase adjustment values based on which AFE units are active, avoiding the need for complex real-time phase measurement and adjustment circuitry while maintaining synchronized output.
Data Source
AI summary
Conventional analog front ends or AFEs for scanners are implemented using multiple integrated circuits or ICs. As a result, there is typically a problem of skew (due at least in part to manufacturing process variations) for these different ICs in the AFE. Here, an AFE is provided which serializes input data so as to compensate for skew.