Skew Measurement via Clock Recovery Loop Locking
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Solution Overview
Problem
Existing backplane systems in electronic devices face challenges in effectively measuring and controlling the skew between clock and data signals, which is crucial for compliance with specifications, due to the lack of efficient and automated measurement methods.
Innovation Solution
A skew measurement system and method that connects each signal to a clock recovery loop, determining phase offsets, and calculating skew measurements by comparing locked states of different signals, utilizing a clock phase generator, phase detector, and adaptation block to generate and adjust clock signals for accurate skew determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automated measurement systems are implemented to measure skew, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The clock recovery loop automatically adjusts its internal clock phase to match the incoming data signal phase, eliminating the need for external automated measurement equipment. The system self-measures skew by observing the locked state of the loop, transforming a complex external measurement problem into a simple internal state observation.
Solution Approach 2:
The patent introduces a clock recovery loop as an intermediary mechanism between the data signal and the measurement system. This loop acts as a mediator that converts the skew measurement problem into a phase locking problem, where the locked state directly indicates the skew value without requiring complex external measurement apparatus.
2Productivity
If manual skew measurement methods are used, then device complexity is reduced, but productivity decreases
Solution Approach 1:
The clock recovery loop performs self-adjustment and self-measurement of skew automatically. The adaptation block continuously adjusts the internal clock phase based on the data signal, and the locked state provides direct indication of the skew value, eliminating manual measurement operations and significantly improving productivity.
Solution Approach 2:
The patent implements a feedback mechanism where the phase detector compares the recovered clock signal with the incoming data signal, and the adaptation block uses this comparison to adjust the internal clock phase. This closed-loop feedback system automatically measures and compensates for skew, improving measurement efficiency without requiring complex external systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise and efficient skew measurement, ensuring compliance with specifications by accurately determining relative skew between signals, allowing for on-chip delay equalization and compensation for off-chip skews, thereby improving data transmission reliability.
Implementation Method 1
a phase detector configured to compare the output clock signal with an input data signal and to generate a comparison output
Implementation Method 2
The locked state of the clock recovery loop is used as an indicator of the skew of the data signal relative to the internal clock of the clock recovery loop
Data Source
AI summary
A skew measurement system and method wherein each of the signals among which the skew is to be determined is connected one at a time to a clock recovery loop. The locked state of the clock recovery loop is used as an indicator of the skew of the data signal relative to the internal clock of the clock recovery loop. By measuring the difference between the locked state of different signals, their relative skew can be measured.