Receiver Clock Data Recovery with Non-Destructive IQ Calibration
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Solution Overview
Problem
In semiconductor chips, the sampling time in the middle of the data eye can drift, requiring realignment of the sampling point, which typically involves interrupting the data stream, posing challenges in maintaining continuous data processing.
Innovation Solution
A non-destructive calibration scheme is implemented using a periodic receiver clock data recovery method with dynamic data edge paths, where the in-phase and quadrature (IQ) link calibration involves swapping data and edge paths without disrupting the data stream, allowing for IQ offset determination without disturbing the data processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sampling point is realigned by interrupting the data stream, then the sampling alignment accuracy is improved, but the data processing continuity deteriorates
Solution Approach 1:
The patent divides the data path into two separate paths: a data path for normal data processing and an edge path for sampling alignment calibration. By segmenting the calibration function into a dedicated edge path, the system can perform sampling alignment adjustments without interrupting the main data stream, thus maintaining both accuracy and continuity.
Solution Approach 2:
The patent introduces an edge path as an intermediary structure that handles sampling alignment calibration separately from the main data path. This intermediary path allows calibration operations to occur without directly interfering with data processing, resolving the contradiction between alignment accuracy and processing continuity.
2Measurement precision
If the data path is recalibrated, then the sampling alignment accuracy is improved, but the data stream interruption increases
Solution Approach 1:
The calibration function is segmented into a separate edge path that operates independently from the data path. This allows calibration to occur in parallel without requiring data stream interruption, eliminating time loss while maintaining alignment accuracy.
Solution Approach 2:
The patent ensures continuous data processing by maintaining the data path operational while performing calibration on the separate edge path. The useful action of data processing continues uninterrupted while calibration proceeds independently, preventing any loss of time.
3Productivity
If a non-destructive calibration scheme is implemented with path swapping, then the data processing continuity is maintained, but the device complexity increases
Solution Approach 1:
The patent merges the data path and edge path into a unified structure that shares common resources such as multiplexers and clock domains. By combining these paths in a slower clock domain with shared components, the system reduces overall complexity while maintaining the ability to perform non-destructive calibration with path swapping.
Solution Approach 2:
The multiplexers and clock divider circuits serve multiple functions: they handle both normal data processing and calibration operations. This multi-functionality reduces the need for separate dedicated components, thereby reducing device complexity while maintaining data processing continuity during calibration.
Data Source
AI summary
Systems, apparatuses, and methods for implementing a periodic receiver clock data recovery scheme with dynamic data edge paths are disclosed. An IQ link calibration scheme performs a non-destructive data and edge path switch to determine an IQ offset without disturbing the data. A data path and an edge path pass through multiple stages of deserializers to widen the data path, with the deserializers clocked by clock divided versions of the original data and edge clocks. To initiate a calibration routine, the edge clock is aligned with the data clock, and then data and edge paths are swapped at a common point in a slower clock domain. The data path is then calibrated while the edge path carries the data signal. After the data path is calibrated, the edge and data paths are swapped back to the original configuration.