Time-Interleaved Receiver Phase Alignment Under Pulse Width Distortion
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Solution Overview
Problem
Conventional clock and data recovery systems struggle to maintain phase alignment of multiple parallel signal paths in high-speed communication systems, especially when faced with transmitter impairments like pulse width distortion, leading to data sampling errors.
Innovation Solution
A clock and data recovery circuit with a phase detector that calculates a sum of gradients for multiple data interleaves and uses configurable delay elements to adjust the multiphase clock signals, ensuring accurate sampling by controlling the phase offset loop with accumulated differential gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple parallel signal paths (interleaves) are used to increase data rate, then productivity is improved, but maintaining phase alignment across all interleaves becomes more complex
Solution Approach 1:
The system segments the data stream into multiple parallel interleaves, each processed independently through its own phase detector and gradient calculator. This allows the high data rate to be achieved through parallel processing while each individual interleave path maintains manageable complexity. The segmentation is evident in the multiple phase detectors (220, 222, 224) and gradient calculators (202, 204, 206) operating on separate interleaved data paths.
Solution Approach 2:
The system merges the gradient information from all interleaves by calculating a sum of gradients that is then accumulated to control the multiphase clock. This combining approach allows the system to maintain phase alignment across all interleaves simultaneously, addressing the complexity issue while preserving the high data rate benefit of multiple parallel paths.
2Device complexity
If conventional clock and data recovery is used, then device complexity is kept simple, but phase alignment cannot be maintained in presence of transmitter impairments like pulse width distortion
Solution Approach 1:
The system implements feedback by using phase detectors to continuously monitor phase alignment and gradient calculators to compute timing errors. These feedback signals are accumulated and used to dynamically adjust the multiphase clock phases, ensuring continuous phase alignment compensation for transmitter impairments like pulse width distortion while maintaining manageable system complexity.
Solution Approach 2:
The system employs dynamic phase adjustment through configurable delay elements that can be individually tuned for each interleave path. This dynamic capability allows the system to adapt to varying transmitter impairments and maintain reliable phase alignment, moving beyond static conventional recovery methods while keeping each individual adjustment mechanism relatively simple.
3Measurement precision
If phase alignment is maintained across all interleaves, then data sampling accuracy is improved, but the system becomes less adaptable to transmitter errors like pulse width distortion
Solution Approach 1:
The system applies local quality by allowing each interleave path to have its own specific phase offset and delay configuration tailored to its particular timing characteristics and errors. This enables precise local optimization of sampling accuracy for each path while the overall system maintains adaptability through individualized gradient accumulation and phase adjustment for each interleave, rather than forcing a uniform approach.
Data Source
AI summary
This disclosure relates to a receiver comprising a clock and data recovery loop and a phase offset loop. The clock and data recovery loop may be controlled by a sum of gradients for a plurality of data interleaves. The phase offset loop may be controlled by an accumulated differential gradient for each of the data interleaves.