Time-Interleaved Receiver Clock Phase Adjustment for Timing Skew
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Solution Overview
Problem
Clock timing skew occurs in time-interleaved receivers due to manufacturing variations, leading to performance degradation, and existing methods fail to effectively detect and mitigate this issue.
Innovation Solution
A method is implemented in a time-interleaved receiver that generates multiple clocks with the same frequency but different phases, determines intersymbol interference (ISI) values for each clock, and adjusts the clock phase based on these values to reduce or eliminate timing skew by comparing them to a reference ISI value, typically the average, and adjusting the phase in response to differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple clocks are generated with different phases to achieve time-interleaved sampling, then the overall sampling rate is increased, but clock timing skew occurs due to manufacturing variations
Solution Approach 1:
The patent implements a feedback mechanism where ISI values are continuously measured for each clock phase and used to adjust the clock phases dynamically. The system computes ISI values by comparing sampled signals with expected values, then uses these measurements to generate control signals that adjust the clock generator phases, creating a closed-loop system that compensates for manufacturing variations and maintains precise timing relationships.
Solution Approach 2:
The patent changes the phase parameter of the clocks dynamically based on measured ISI values. By adjusting the phase of individual clocks relative to each other, the system compensates for timing skew caused by manufacturing variations. The phase adjustments are made in response to ISI measurements, allowing the system to adapt the clock timing parameters to achieve optimal sampling alignment.
2Ease of operation
If clock timing skew is not corrected, then the system operates with manufacturing variations, but receiver performance degrades due to timing errors
Solution Approach 1:
The system continuously monitors timing accuracy by measuring ISI values for each clock phase and uses this feedback to adjust clock phases dynamically. This closed-loop control ensures that timing skew is compensated in real-time, maintaining reliable receiver performance without requiring manual intervention or complex calibration procedures.
Solution Approach 2:
The system performs self-correction of timing skew by automatically measuring its own ISI values and adjusting its clock phases accordingly. The receiver monitors its own timing accuracy and makes autonomous adjustments to maintain optimal performance, eliminating the need for external calibration or manual intervention.
3Manufacturing precision
If ISI values are measured and used to adjust clock phases, then timing skew is reduced, but the system complexity increases
Solution Approach 1:
The patent uses the existing signal processing circuitry to perform multiple functions: the same circuits that process the main signal are also used to measure ISI values and generate control signals for clock adjustment. By making the existing circuitry multi-functional, the system avoids adding separate dedicated measurement and control circuits, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The feedback mechanism uses simple ISI measurements and proportional adjustments rather than complex control algorithms. The system measures ISI values and applies straightforward phase corrections based on these measurements, using minimal additional circuitry to implement the feedback loop. This keeps the complexity increase manageable while achieving effective timing skew compensation.
Data Source
AI summary
Clock timing skew may occur during operation of a time-interleaved receiver. It would be beneficial to try to determine if there is timing skew, and if there is, then address it, such as by reducing or eliminating some or all of the timing skew. Embodiments are described herein that may achieve this. In one embodiment, a method includes generating at least two clocks having the same frequency but a different phase. Intersymbol interference (ISI) values are then determined, one for each of the clocks, by: for each clock, sampling a signal using the clock and determining a value representing ISI based on the sampled signal. A clock phase of at least one of the clocks is adjusted in response to at least one of the ISI values being different from a reference ISI value.