Clock Distribution Using PWM Offset Data for Precise Synchronization

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Solution Overview

Problem

Current methods for distributing clock signals in network systems fail to provide sufficiently accurate clock signals to meet the precise timing requirements of modern networks, particularly due to quantization errors in digital measurements and lack of feedback in differential methods.

Innovation Solution

The method involves determining frequency and phase offset data between clock signals and transmitting these on a pulse-width modulated clock signal, allowing for precise recovery and adjustment of clock signals at the receiving device, thereby correcting for quantization errors and ensuring accurate clock synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital phase-locked loops are used to distribute clock signals, then clock distribution is achieved, but quantization errors in digital measurements reduce accuracy

Engineering Contradiction:
Improveclock signal accuracyVSAvoiddigital measurement system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism where phase offset data is periodically measured between the first clock signal and other clock signals, and frequency offset adjustments are made based on these measurements. This closed-loop feedback system continuously corrects quantization errors in digital measurements, thereby improving clock signal accuracy without requiring complete system redesign.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the approach from static digital frequency synthesis to dynamic parameter adjustment. By periodically measuring phase offsets and adjusting frequency offset parameters based on these measurements, the system adapts to and corrects quantization errors, improving measurement precision while maintaining digital system architecture.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If differential methods are used for clock distribution, then implementation is simplified, but lack of feedback reduces accuracy

Engineering Contradiction:
Improveclock distribution implementationVSAvoidclock signal accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent adds a feedback mechanism to the differential method by periodically measuring phase offsets between clock signals and using these measurements to adjust frequency offsets. This maintains the simplicity of differential implementation while eliminating the accuracy limitation caused by lack of feedback.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If pulse-width modulation is used to transmit clock signals, then frequency and phase offset data can be transmitted, but the system complexity increases

Engineering Contradiction:
Improveclock signal recovery accuracyVSAvoidmodulation and demodulation system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses pulse-width modulation to simultaneously transmit multiple types of information (frequency offset data and phase offset data) on the clock signal itself. This multi-functional approach allows accurate clock signal recovery without requiring separate communication channels, thereby reducing overall system complexity despite the added modulation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Measurement precision

If periodic phase offset measurement is implemented, then quantization errors are corrected, but measurement and processing time increases

Engineering Contradiction:
Improveclock signal accuracyVSAvoidphase offset measurement and processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements periodic phase offset measurement rather than continuous measurement. By measuring phase offsets at regular intervals and adjusting frequency offsets based on these periodic measurements, the system achieves quantization error correction while minimizing the time lost to measurement and processing activities.

Inventive Principle:
Principle #19Periodic action

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 approach ensures that clock signals are distributed with high precision, meeting the stringent timing requirements of modern networks by periodically measuring and adjusting for phase drift, thereby reducing recovery errors and maintaining synchronization across multiple frequencies.

Implementation Method 1

transmitting the first clock signal, the frequency offset data, and the phase offset data on a pulse-width modulated clock signal

Methodology Applied
Scientific EffectPulse-width modulation: Phase Modulation

Data Source

PatentEP3599736B1Zero offset clock distribution
Publication Date: 2024.04.17 INTEGRATED DEVICE TECH INC
  • EP3599736B1 patent drawingFigure 1
  • EP3599736B1 patent drawingFigure 2~3

AI summary

A method of distributing clock signals includes receiving a plurality of clock signals into a corresponding plurality of processing blocks; determining frequency offset data between a first clock signal of the plurality of clock signals and each of the other clock signals of the plurality of clock signals; periodically determining phase offset data between the first clock signal and the other clock signals; and transmitting the first clock signal, the frequency offset data, and the phase offset data on a pulse-width modulated clock signal. The method includes receiving a modulated clock signal, the modulated clock signal include a carrier clock signal, a frequency offset data, and a phase offset data on a pulse-width modulated clock signal; and recovering a plurality of clock signals based on the first clock signal, the frequency offset data, and the phase offset data.