Clock Frequency Feedback Smoothing for Jitter-Stable Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing communication systems, particularly satellite communication systems, face challenges with clock synchronization due to significant jitter in clock signals, leading to instability and errors in frequency synthesis, which affect communication performance and throughput.
Innovation Solution
Implementing a smoothing filter in the feedback loop of clock systems to adjust the rate of clock frequency changes, using functions like weighted averages or exponential smoothing to reduce jitter and enhance stability, achieving frequency stability of 5 parts per billion or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional clock synchronization methods are used, then communication systems can operate with synchronized clocks, but significant jitter in clock signals causes instability and errors in frequency synthesis
Solution Approach 1:
A smoothing filter is introduced as an intermediary component between the feedback loop controller and the clock frequency adjustment mechanism. This filter processes the frequency adjustment commands, applying exponential smoothing or weighted averaging to reduce jitter before the adjustments are applied to the clock signal, thereby stabilizing the clock while maintaining synchronization
Solution Approach 2:
The system changes the parameter of clock frequency adjustment by applying smoothing functions (exponential smoothing, weighted averages) to the frequency adjustment commands. This transforms the raw feedback signals into stabilized adjustment parameters that reduce jitter while maintaining the necessary frequency corrections for synchronization
2Measurement precision
If clock frequency adjustments are made frequently to maintain synchronization, then timing accuracy is improved, but jitter increases causing instability in frequency synthesis
Solution Approach 1:
The smoothing filter acts as a mediator that receives frequent frequency adjustment commands from the feedback loop and transforms them into stabilized adjustment signals. This allows the system to maintain precise timing synchronization through frequent updates while the filter eliminates the jitter that would otherwise cause instability in frequency synthesis
Solution Approach 2:
The smoothing filter performs preliminary processing on frequency adjustment commands before they are applied to the clock signal. By pre-smoothing the adjustment commands using exponential smoothing or weighted averaging, the system prepares stabilized control signals that maintain timing precision without introducing jitter to the frequency synthesis process
Data Source
AI summary
Methods, systems, and apparatus, for enhanced clock frequency control. In some implementations, a clock system tracks time using a clock signal having a clock frequency. An interface receives a time reference from a reference clock, and a feedback loop synchronizes the clock system with the reference clock. The feedback loop includes a feedback loop controller configured to determine a clock frequency adjustment for the clock system based on an offset between the time reference and a time indicated by the clock system. The feedback loop also includes a smoothing filter configured to alter the clock frequency adjustment determined using the feedback loop controller. The feedback loop updates the clock frequency of the clock system based on the altered clock frequency adjustment.