Serial Repeater Clock Synchronization Using Phase Detection
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Solution Overview
Problem
The synchronization of write and read frequencies in serial repeaters is challenging due to manufacturing variations, leading to inconsistencies in digital clock frequencies across devices, particularly in photonic integrated circuits and other signal-converting components.
Innovation Solution
An apparatus comprising a phase detector and phase rotator, coupled with a phase locked loop, detects frequency mismatches between the write and read frequencies and adjusts the read frequency of the serializer through a pacing signal to synchronize them, using code sequences to control incremental changes in the read frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital clocks of different devices operate at unique frequencies due to manufacturing variations, then device manufacturing is simplified and more adaptable, but frequency synchronization between devices deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the receiving device detects the frequency difference between its local clock and the transmitting device's clock, then generates a control signal to adjust the read frequency of the serializer. This closed-loop feedback system continuously monitors and corrects frequency mismatches, ensuring reliable synchronization despite manufacturing variations that allow each device to operate at slightly different frequencies.
2Device complexity
If serial repeater read and write frequencies are not synchronized, then device operation is simpler without complex control circuits, but data transmission accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary frequency control mechanism that mediates between the serializer's read frequency and the deserializer's write frequency. The phase detector acts as an intermediary that compares the two frequencies and generates a control signal through a phase-locked loop to adjust the serializer's read frequency, ensuring accurate data transmission without requiring complex synchronization protocols or changing the fundamental simple operation of the serial repeater.
3Reliability
If phase detector and phase rotator circuits are added to synchronize frequencies, then frequency synchronization is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical or hardware-based frequency synchronization mechanisms with an electronic control approach using a phase detector and phase-locked loop. Instead of using complex timing circuits or mechanical synchronizers, the system uses electronic detection of frequency differences and electronic adjustment of the serializer's clock frequency, achieving reliable synchronization with a more compact and integrable electronic circuit design.
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 solution effectively reduces frequency mismatches, ensuring synchronized operation of write and read frequencies, thereby improving data transmission accuracy and reliability across devices with varying clock frequencies.
Implementation Method 1
a phase detector having a first detector input line coupled to a deserializer of a serial repeater to detect a write frequency of the deserializer and a second detector input line coupled to a serializer of the serial repeater to detect a read frequency of the serializer
Implementation Method 2
a phase rotator having a first rotator input line coupled to a phase locked loop (PLL) to receive a clock signal therefrom
Data Source
AI summary
Embodiments of the present disclosure provide an apparatus including: a phase detector for detecting a write frequency of a deserializer and a read frequency of a serializer, such that the phase detector outputs a first code sequence in response to the write frequency being greater than the read frequency, or a second code sequence at the rotator input in response to the write frequency being less than the read frequency; and a phase rotator for receiving the first code sequence or the second code sequence from the phase rotator to transmit a pacing signal having the read frequency to the deserializer, wherein the pacing signal causes the read frequency to increase or decrease based on whether the read frequency is different from the write frequency.