Clock Recovery and Path Switching in Daisy-Chain Serial TDM Links

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Solution Overview

Problem

In daisy-chained data transmission systems, dynamic switching of data paths and network synchronization is difficult, leading to communication disruptions when one device becomes unnecessary, and the clock transmission path cannot be easily disconnected.

Innovation Solution

A serial data transmission device with a controller that adjusts transmission and a clock recovery device using a fractional PLL to dynamically switch data paths and enhance stability, allowing for flexible band allocation and clock synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If daisy-chained data transmission devices use a single clock transmission path for synchronization, then network synchronization is achieved, but communication disruptions occur when one device becomes unnecessary and cannot be removed

Engineering Contradiction:
Improvenetwork synchronizationVSAvoiddynamic switching of data paths
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent segments the clock transmission function from the data transmission function by introducing independent clock transmission paths for each data transmission path. This allows the clock function to be distributed across multiple paths rather than relying on a single centralized clock path, enabling individual paths to be activated or deactivated independently based on operational needs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic switching capability by providing multiple clock transmission paths that can be selectively activated. The system can dynamically switch between different clock paths depending on which data transmission paths are currently in use, allowing the network to adapt its clock distribution architecture to match the actual data flow requirements without disrupting synchronization.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If a single data transmission device serves as the clock basis for the entire network, then synchronization is maintained, but the device cannot be removed even when unnecessary

Engineering Contradiction:
Improveclock synchronizationVSAvoidstability to failure
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent extracts the clock transmission function from the data transmission function, creating independent clock transmission paths. This separation allows the clock basis function to be distributed across multiple devices rather than concentrated in a single device, so that if one device becomes unnecessary or fails, other devices can continue to provide clock synchronization through their dedicated clock paths.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent enables dynamic change of the clock basis parameter by allowing different devices to serve as clock sources depending on operational requirements. The system can switch which device provides the reference clock signal, changing the clock basis parameter dynamically rather than being fixed to a single device, thereby improving both reliability and adaptability.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the serial transmission path also serves as the clock transmission path, then circuit configuration is simplified, but communication issues disrupt both data and clock transmission

Engineering Contradiction:
Improvecircuit configurationVSAvoidcommunication stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the transmission functions by providing separate clock transmission paths independent of the data transmission paths. This segmentation ensures that clock signals travel through dedicated channels rather than sharing the data transmission medium, so that data communication issues do not affect clock transmission and vice versa, thereby improving overall system reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dedicated clock transmission paths that act as intermediary channels between data transmission devices. These intermediary clock paths provide a separate communication medium for synchronization signals, isolating the clock transmission function from data transmission issues and ensuring that clock synchronization remains stable even when data communication experiences problems.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables dynamic switching of data paths and improved communication stability in daisy-chained networks by adjusting transmission and clock recovery, even in the presence of clock fluctuations.

Implementation Method 1

a clock recovery circuit that recovers a clock by means of a fractional PLL in accordance with reception of the data by the receiver

Methodology Applied
Scientific EffectPhase-locked loop (PLL):

Implementation Method 2

the clock recovery circuit calculates a division ratio of a frequency divider of the fractional PLL from a value obtained by computing a counter value

Methodology Applied
Scientific EffectFrequency division:

Data Source

PatentEP3723308B1Serial data transmission device and clock reproduction device
Publication Date: 2025.07.02 SONY SEMICON SOLUTIONS CORP
  • EP3723308B1 patent drawingFigure 1
  • EP3723308B1 patent drawingFigure 2
  • EP3723308B1 patent drawingFigure 3

AI summary

[Problem to be Solved] To provide a serial data transmission device that makes it possible to dynamically switch a band or a data transmission path and enhance the stability to failure while multiplexing and transmitting data by a TDM method when serial data is transmitted between a plurality of daisy-chained data transmission devices. [Solution] There is provided a serial data transmission device including: a receiver that receives data serially transmitted by a time-division multiplex method from another device daisy-chained to the serial data transmission device; a transmitter that serially transmits data by the time-division multiplex method to another device daisy-chained to the serial data transmission device; and a controller that controls serial transmission by the receiver and the transmitter, in which the controller performs control to make the serial transmission by the transmitter adjustable.