PN Code Modulation for Synchronization in High-Speed Digital Circuits
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Solution Overview
Problem
As clock frequencies increase, synchronizing signals across multiple devices becomes challenging due to sampling noise and jitter, which can lead to inaccurate reading of synchronization and data signals in multi-device systems.
Innovation Solution
A system and method that uses a pseudo-noise (PN) code with a single-peak auto-correlation function to modulate state-variable signals, allowing for recovery of synchronization even with errors caused by jitter or sampling noise, by employing digital spread spectrum techniques to synchronize multiple devices through a wire line connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If clock frequency is increased to improve productivity, then data processing speed is improved, but synchronization accuracy deteriorates due to sampling noise and jitter
Solution Approach 1:
The patent changes the parameter of signal representation by transforming the synchronization signal into spread spectrum form using pseudo-random code modulation. This transformation allows the signal to maintain its synchronization function while becoming more robust against jitter and sampling noise, thereby resolving the contradiction between high clock frequency operation and synchronization accuracy
Solution Approach 2:
The patent introduces pseudo-random code sequences as an intermediary between the master and slave devices. These codes act as a mediator that carries synchronization information in a form that is resilient to noise and jitter, enabling accurate synchronization even at high clock frequencies where direct signaling would fail
2Reliability
If spread spectrum modulation is applied to improve synchronization robustness, then noise immunity is improved, but signal complexity increases
Solution Approach 1:
The patent segments the synchronization signal into multiple chips by modulating with pseudo-random code sequences. This segmentation spreads the signal energy across a wider bandwidth and creates redundancy that improves noise immunity, while the modular nature of code-based modulation keeps the implementation complexity manageable
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 effective phase synchronization of state machines in systems with different data rates, allowing for reliable communication of state-variable and time base information, even in the presence of noise and jitter, by using a PN code that can recover synchronization and tolerate errors.
Implementation Method 1
A master device provides a state-variable signal which is modulated with a pseudo-noise (PN) code. The PN code includes a number of pseudo-random bits that are sampled at a rate greater than that of the state-variable signal.
Implementation Method 2
By using a PN code that has a single-peak auto -correlation function, the state-variable signal can be recovered even if there are errors in the signal caused by jitter or sampling noise.
Data Source
AI summary
A method for generating a data signal for synchronizing one or more electrically coupled digital receivers is disclosed. A data signal having a data rate is modulated with a pseudo-noise (PN) code having a data rate greater than the data rate of the data signal. The modulated data signal is demodulated by a receiver using the PN code. A correlation value is generated and is compared to a predetermined value to indicate phase synchronization. If the receiver is in phase synchronization with the transmitter, the received demodulated data signal is passed.