Phase Offset Compensator Using Feedback and Feed-Forward Loops
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Solution Overview
Problem
Existing carrier recovery systems in digital communication face limitations in compensating both slowly and rapidly varying phase fluctuations, with feedback loop structures being inadequate for rapid variations and complex feed-forward approaches being overly complex.
Innovation Solution
A phase offset compensator that combines a feedback loop for slowly varying phase offsets and a feed-forward loop for rapidly varying phase offsets, sharing a common phase offset detector and filters, allowing for reduced complexity and serial concatenation of the loops to achieve effective compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a feedback loop structure is used for carrier recovery, then slowly varying phase fluctuations can be compensated, but rapidly varying phase fluctuations cannot be compensated effectively
Solution Approach 1:
The patent divides the phase offset compensation task into two segments: a feedback loop for slowly varying phase offsets and a feed-forward loop for rapidly varying phase offsets. This segmentation allows each loop to be optimized for its specific function, resolving the contradiction between handling slow and fast phase variations.
Solution Approach 2:
The patent employs dynamic filtering with different time constants for the feedback and feed-forward loops. The feedback loop uses a longer time constant for slow variations, while the feed-forward loop uses a shorter time constant for rapid variations, enabling the system to adapt to different phase fluctuation speeds.
2Measurement precision
If a feed-forward approach is used to compensate rapidly varying phase offsets, then compensation accuracy improves, but system complexity increases considerably
Solution Approach 1:
The patent merges the feedback loop and feed-forward loop into a unified phase offset compensator that shares common components including the phase offset detector and filtering structures. This combination achieves high compensation accuracy while reducing overall system complexity through component sharing.
Solution Approach 2:
The phase offset detector serves dual functions by providing detection signals to both the feedback loop and feed-forward loop simultaneously. This multi-functionality reduces the need for separate detection mechanisms, thereby lowering system complexity while maintaining high precision compensation.
3Adaptability or versatility
If separate feedback loop and feed-forward loop are deployed, then both slowly and rapidly varying phase offsets can be compensated, but system complexity increases
Solution Approach 1:
The patent combines separate feedback and feed-forward loops into an integrated structure where both loops share the phase offset detector and filtering resources. This merging maintains the versatility to handle both slow and fast phase variations while reducing complexity through shared components.
Solution Approach 2:
The patent introduces a shared phase offset detector as an intermediary that serves both the feedback and feed-forward loops. This mediator structure enables both loops to access phase offset information without requiring duplicate detection mechanisms, thereby reducing overall system complexity while maintaining comprehensive compensation capability.
Data Source
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AI summary
The invention relates to a phase offset compensator for compensating a phase offset, the phase offset comprising a first phase sub-offset and a second phase sub-offset. The phase offset compensator comprises a feedback loop (103) comprising a first loop filter (105), the feedback loop (103) being configured to compensate the first phase sub-offset of the phase offset, and a feed forward loop (107) comprising a second loop filter (109), the feed forward loop (107) being configured to compensate the second phase sub-offset of the phase offset.