Clock Device In-Band Calibration for Antenna Cable Delay
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Solution Overview
Problem
Existing clock devices in data networks face challenges in maintaining accurate time synchronization due to varying antenna cable delays caused by factors like temperature variations and aging, which are difficult to predict or measure during installation.
Innovation Solution
Implementing an in-band calibration method within the clock device to continuously sample and compensate for antenna cable delays by generating pulses, measuring roundtrip delays, and applying time corrections based on these measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If preliminary calibration is performed during installation, then initial time synchronization accuracy is improved, but the system cannot adapt to cable delay variations caused by temperature and aging
Solution Approach 1:
The system transitions from static preliminary calibration to dynamic continuous calibration by repeatedly performing TT protocols at different times. The calibration process is made adaptive to changing conditions (temperature, aging) through multiple measurements and statistical analysis, allowing the system to track and compensate for cable delay variations over time.
Solution Approach 2:
The system implements feedback by using the results of repeated TT protocols to continuously update calibration parameters. The statistical analysis of measurement results provides feedback on cable delay characteristics, which is then used to adjust time synchronization calculations, creating a closed-loop system that adapts to changing conditions.
2Device complexity
If cable delay is assumed constant based on installation specifications, then device complexity is reduced, but time synchronization accuracy deteriorates due to environmental variations
Solution Approach 1:
The system performs preliminary actions by conducting multiple TT protocols before final calibration to establish baseline cable delay characteristics. This preliminary measurement phase allows the system to gather statistical data about cable behavior under different conditions, which is then used to improve subsequent synchronization accuracy without requiring complex real-time monitoring.
Solution Approach 2:
The system changes parameters by using statistical measures (mean, standard deviation) derived from multiple measurements to represent cable delay characteristics. Instead of relying on a single fixed value from installation specifications, the system uses dynamically determined parameters that reflect actual cable behavior, improving accuracy while maintaining relatively simple device complexity.
3Measurement precision
If continuous monitoring of cable delay is implemented, then time synchronization accuracy is improved, but use of energy and measurement resources increases
Solution Approach 1:
The system implements periodic action by performing TT protocols at scheduled intervals rather than continuously. This approach maintains time synchronization accuracy by regularly updating calibration data while consuming energy only when necessary. The periodic measurements are sufficient to detect cable delay variations without requiring constant monitoring, thus reducing overall energy consumption.
Solution Approach 2:
The system uses partial action by performing a limited number of TT protocols that provide sufficient statistical data for accurate calibration without excessive measurements. By determining an optimal number of repetitions based on required precision levels, the system achieves adequate measurement precision while avoiding unnecessary energy consumption from excessive monitoring.
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 enhances time synchronization accuracy by dynamically adjusting for cable delay variations, eliminating the need for prior knowledge of cable length and specifications, and detecting cable damage.
Implementation Method 1
measuring, by the measurement tool, the roundtrip delay between the generated pulse and a measured signal reflected by antenna, thereby obtaining a cable delay
Data Source
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AI summary
There is provided a technique for calibrating a clock device operatively connected to an antenna and receiving precision time therefrom via a cable. The technique enables increasing the accuracy of the clock device by in-band time calibration thereof with the help of continuously sampling antenna cable delays and enabling respective time corrections. The method of calibrating comprises: a) upon disabling antenna's powering, generating by a measurement tool implemented within the clock device a pulse toward the unpowered antenna; b) measuring, by the measurement tool, the roundtrip delay between the generated pulse and a measured signal reflected by the antenna, thereby obtaining a cable delay; and c) providing time correction in the clock device in accordance with the cable delay. Continuously repeating operations a) - c) can enable in-band compensation for varying cable delay.