Clock Calibration with Continuous Antenna Cable Delay Compensation
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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 temperature variations and aging, which are difficult to predict and compensate for during installation.
Innovation Solution
A method and device for continuous in-band calibration of clock devices that involves disabling antenna power to measure roundtrip delays and adjust time signals accordingly, using a measurement module to sample and compensate for cable delays, enabling continuous compensation for varying delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cable delay calibration is performed during installation using cable length and specification, then initial time synchronization accuracy is improved, but the system cannot compensate for temperature variations and aging effects that occur during operation
Solution Approach 1:
The patent transitions from static calibration (performed once during installation) to dynamic calibration (continuously performed during operation). The system now adapts to changing cable characteristics caused by temperature variations and aging by repeatedly measuring roundtrip delays and updating calibration parameters in real-time, resolving the contradiction between initial accuracy and long-term stability.
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously measures the roundtrip delay of time signals through the antenna cable, compares it with expected values, and adjusts calibration parameters accordingly. This closed-loop feedback enables automatic compensation for temperature and aging effects, maintaining time synchronization accuracy throughout the operational lifecycle.
2Measurement precision
If continuous calibration is performed by disabling antenna power and measuring roundtrip delays, then time synchronization accuracy is improved, but device complexity increases due to additional measurement modules and calibration procedures
Solution Approach 1:
The patent makes the antenna cable serve multiple functions: it acts as both the transmission medium for GNSS signals and the test medium for calibration measurements. By utilizing the existing cable infrastructure for dual purposes (signal transmission and delay measurement), the system achieves continuous calibration without adding separate physical test cables or complex external measurement equipment.
Solution Approach 2:
The system performs its own calibration using internally generated test signals and an integrated measurement module, eliminating the need for external test devices or manual calibration procedures. The clock device autonomously measures roundtrip delays, calculates cable delays, and adjusts its timing parameters without external intervention, reducing operational complexity despite the added calibration capability.
3Measurement precision
If cable delay is measured using external test devices during installation, then calibration accuracy is improved, but ease of operation deteriorates due to requiring external equipment and manual calibration processes
Solution Approach 1:
The system performs its own calibration using internally generated test signals and an integrated measurement module, eliminating the need for external test devices or manual calibration procedures. The clock device autonomously measures roundtrip delays, calculates cable delays, and adjusts its timing parameters without external intervention, reducing operational complexity despite the added calibration capability.
Solution Approach 2:
The patent uses software control logic as an intermediary to manage the calibration process, coordinating the disabling of antenna power, generation of test signals, measurement of roundtrip delays, and updating of calibration parameters. This software-mediated approach simplifies the overall operation by providing a unified control interface and automating the calibration sequence, making the process easier to execute despite the multiple steps involved.
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 eliminating the need to know cable length and specifications, compensating for temperature and aging effects, and detecting cable damage, thus maintaining precise time signals.
Implementation Method 1
measuring, by the measurement module, the roundtrip delay between the generated pulse and a measured signal reflected by the unpowered antenna
Data Source
AI summary
Some embodiments are directed toward a technique for calibrating a clock device operatively connected to an antenna and receiving precision time therefrom via a cable. The technique enables increasing accuracy of the clock device by embedded time calibration with the help of continuously sampling antenna cable delays and enabling respective time corrections. The method includes: a) disabling, by the clock device, antenna's powering thus giving rise to an unpowered antenna; b) generating by a measurement module a pulse and forwarding it toward the unpowered antenna, wherein the measurement module is implemented within the clock device; c) measuring, by the measurement module, the roundtrip delay between the generated pulse and a measured signal reflected by the unpowered antenna, thereby obtaining a cable delay; and d) providing time calibration in the clock device in accordance with the cable delay. Continuously repeating operations a)-d) can enable embedded compensation for varying cable delay.