Clock Recovery Circuit for Dynamic TDM Serial Path Switching
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Solution Overview
Problem
In daisy-chained serial data transmission systems, dynamic switching of data transmission paths and clock synchronization is challenging, leading to instability and disruption when issues arise in communication between devices, as the clock transmission path is shared with data transmission paths.
Innovation Solution
A serial data transmission device with a receiver, transmitter, and controller that uses time-division multiplexing (TDM) to dynamically adjust data transmission paths and includes a clock recovery circuit with a fractional PLL to manage clock fluctuations, allowing for flexible band allocation and improved stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a single data transmission device is used as the clock basis for the entire network, then clock synchronization is achieved, but the system cannot dynamically switch devices and communication stability is reduced when issues arise
Solution Approach 1:
The patent divides the clock synchronization function into two independent paths: a data transmission path and a dedicated clock transmission path. Each device can independently manage its clock synchronization through the dedicated path, allowing individual devices to be replaced or switched without affecting the entire network's clock synchronization stability
Solution Approach 2:
The patent introduces a dedicated clock transmission path as an intermediary between devices, separating the clock synchronization function from the data transmission function. This intermediary path enables stable clock distribution while allowing flexible changes in the data transmission path
2Productivity
If the serial transmission path is used for both data and clock transmission, then resource utilization is improved, but communication disruption occurs when issues arise in the shared path
Solution Approach 1:
The patent segments the transmission functions by creating separate dedicated clock transmission paths from each device, distinguishing them from the main data transmission path. This segmentation ensures that clock synchronization remains reliable even when data transmission experiences issues
Solution Approach 2:
The patent applies different transmission qualities to different functions: the dedicated clock transmission path provides high reliability and stability for time-critical synchronization, while the data transmission path handles variable data traffic with appropriate bandwidth allocation
3Device complexity
If TDM method is used to multiplex multiple data strings, then circuit complexity is reduced, but dynamic band switching and path selection become challenging
Solution Approach 1:
The patent implements dynamic band allocation within the TDM framework by allowing each device to independently select and allocate time slots for its data transmission. The system can dynamically adjust which devices transmit in which time slots based on current network conditions and requirements, maintaining simplicity while enabling flexibility
Solution Approach 2:
The dedicated clock transmission path serves multiple functions: it provides clock synchronization, enables device identification, and supports dynamic path selection. This multi-functional approach maintains circuit simplicity while enhancing adaptability
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 transmission paths and enhances stability by adjusting clock speeds and allocating resources efficiently, ensuring continuous communication even when individual devices stop transmitting, and reduces the need for large buffers to handle 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
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
Data Source
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.