Bit-Level Retimer With CDR and Phase Interpolation for Signal Integrity
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Solution Overview
Problem
Signal integrity degrades with increasing frequency or data rate and transmission line length without retimers or redrivers, necessitating the use of repeaters to restore signal quality.
Innovation Solution
A retimer circuitry with clock data recovery and phase interpolator circuitry, coupled with digital filters to generate and condition phase control signals, effectively retransmits data packets with improved clock synchronization and noise reduction, enhancing signal integrity across extended transmission systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If transmission line length is increased to extend system reach, then signal integrity degrades due to attenuation and distortion
Solution Approach 1:
A retimer device is introduced as an intermediary component between transmitter and receiver. The retimer includes a clock data recovery circuit that extracts timing information from the transmitted signal, and a phase interpolator that generates a clean local clock signal to retime the data. This intermediary device regenerates the signal with proper timing alignment, compensating for transmission line effects and maintaining signal integrity over extended distances.
2Productivity
If data rate is increased to improve productivity, then signal integrity degrades due to timing jitter and synchronization errors
Solution Approach 1:
The clock data recovery circuit continuously monitors the incoming data signal and generates a phase control signal based on timing deviations. This feedback mechanism adjusts the phase interpolator's output to maintain optimal sampling timing, compensating for jitter and synchronization errors that increase with higher data rates. The closed-loop control ensures timing accuracy is maintained even at elevated data rates.
Solution Approach 2:
The patent replaces traditional analog phase-locked loop (PLL) mechanisms with a digital phase interpolator system. The phase interpolator uses digital logic to generate multiple phase-shifted clock signals and selectively combines them based on feedback, providing finer timing resolution and reduced jitter compared to conventional analog approaches. This substitution enables more precise timing control at high data rates.
3Reliability
If retimer circuitry is added to restore signal integrity, then device complexity increases due to additional clock data recovery and phase interpolator components
Solution Approach 1:
The retimer device performs multiple functions within a single integrated circuit: clock data recovery, phase interpolation, signal retiming, and jitter filtering. By combining these functions in one universal device, the patent avoids the need for separate components for each function, thereby reducing overall system complexity while maintaining signal integrity. The multi-functional design allows the retimer to handle various data rates and transmission conditions through a single reconfigurable architecture.
Data Source
AI summary
Disclosed are some examples of retimer circuitry, systems and methods. In some implementations, clock data recovery circuitry is coupled between a receiver and a transmitter. The clock data recovery circuitry is configured to: extract a data component from an input data signal associated with the receiver, provide the data component to the transmitter, and generate a phase control signal. Phase interpolator circuitry is coupled with the clock data recovery circuitry. The phase interpolator circuitry includes a phase interpolator configured to: receive the phase control signal, generate, based on the phase control signal, an output clock signal, and provide the output clock signal to the transmitter to track data packets of the data component.