Timing Recovery Circuit Initial Phase Generator
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Solution Overview
Problem
Conventional timing recovery circuits face slow convergence and inaccurate sampling due to initial sampling phases often being close to data transitions, leading to false sample data and inadequate timing error estimation.
Innovation Solution
A timing recovery circuit and method that includes an initial phase generator to detect changes in sample data and produce an initial phase, ensuring the sampling signal is aligned close to data peaks, thereby improving convergence and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sampling signal is initialized with an arbitrary phase, then the timing recovery circuit can start operation immediately, but the sampling may occur close to data transitions causing false sample data and slow convergence
Solution Approach 1:
The patent applies preliminary action by implementing an initial phase generator that operates before the main timing recovery process. This generator detects data transitions in the incoming signal and generates an initial sampling phase that is deliberately offset from the data peak, ensuring that the first samples are taken at optimal points away from transitions. This preliminary phase adjustment prevents false sample data and accelerates convergence by avoiding the slow convergence period that would occur with arbitrary phase initialization.
2Productivity
If the sampling signal is aligned close to data peaks, then timing recovery convergence is accelerated and accuracy is improved, but the complexity of the phase generation and control increases
Solution Approach 1:
The patent applies segmentation by dividing the phase generation function into two distinct segments: an initial phase generator that handles the initialization period by detecting data transitions and generating an offset phase, and a main timing recovery controller that takes over once convergence is achieved. This segmentation allows each module to be optimized for its specific function, reducing overall complexity while achieving fast convergence during the critical initial period.
Solution Approach 2:
The initial phase generator acts as an intermediary between the incoming data signal and the main timing recovery controller. It processes the raw data transitions and transforms them into an appropriate initial sampling phase, serving as a bridge that prepares the system for efficient convergence without requiring the main controller to handle the complex initial conditions directly.
3Measurement precision
If sampling occurs at data transitions, then the timing recovery scheme can evaluate timing errors, but the sampling signal cannot reach convergence rapidly due to inaccurate timing error evaluation
Solution Approach 1:
The patent applies preliminary anti-action by deliberately offsetting the initial sampling phase from the data peak position. The initial phase generator detects data transitions and generates a sampling phase that is intentionally shifted away from the transition point. This anti-action prevents the sampling signal from initially operating at incorrect phases close to transitions, thereby avoiding false sample data and the subsequent slow convergence that would result from inaccurate timing error evaluation.
Data Source
AI summary
A circuit and method for timing recovery. The circuit for timing recovery comprises an converter, a timing recovery controller, and a initial phase generator. The converter converts an input signal to sample data with a sampling signal. The timing recovery controller is coupled to the converter, and determines the sampling signal. And the initial phase generator is coupled to the AD converter, detects a change with the sample data only, produces an initial phase based on the change, and controls the sampling signal.