Remote Receiver Phase Synchronization Over Fiber Optic Links
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Solution Overview
Problem
Existing methods for synchronizing remote measurement instruments, such as vector network analyzers, face challenges in accurately determining phase measurements over long distances due to signal attenuation and phase shifts introduced by coaxial cables, limiting the ability to measure phase information effectively in telecommunications networks.
Innovation Solution
The use of a narrow band, low frequency synchronization signal transmitted over a fiber optic cable, which reduces attenuation and allows for accurate phase synchronization between measurement instruments, utilizing a coarse and fine phase detection counter system to determine distance and phase shift, and a duplexer for bidirectional signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a synchronization signal is transmitted through a large signal path to synchronize remote transmitter and receiver, then the transmitter and receiver can be separated by a large distance, but the synchronization signal experiences phase shift and attenuation making phase information difficult to obtain
Solution Approach 1:
The patent introduces a fiber optic cable as an intermediary medium to transmit the synchronization signal between the measurement instrument and remote receiver. This mediator allows signal transmission over long distances while maintaining signal integrity, as fiber optics are immune to electromagnetic interference and signal degradation that plagues traditional coaxial cables. The fiber optic cable acts as a dedicated communication channel that preserves the synchronization signal's phase and timing information.
Solution Approach 2:
The patent replaces the traditional coaxial cable-based synchronization signal transmission with a fiber optic cable system. This substitution eliminates the electromagnetic signal degradation, phase shift, and attenuation issues associated with coaxial cables over long distances. The fiber optic system uses light transmission instead of electrical signals, fundamentally changing the transmission medium to achieve long-distance synchronization without signal degradation.
2Length of stationary object
If a synchronization signal is transmitted over a long distance through traditional coaxial cable, then the transmitter and receiver can be separated, but the signal attenuation increases making synchronization difficult
Solution Approach 1:
The fiber optic cable serves as an intermediary transmission medium that dramatically reduces signal attenuation compared to coaxial cables. The fiber optic cable transmits synchronization signals using light pulses, which experience minimal attenuation over long distances, enabling signal transmission across kilometers without significant loss of energy or signal strength.
Solution Approach 2:
The patent changes the fundamental transmission parameter from electrical signals in coaxial cable to optical signals in fiber optic cable. This parameter change transforms the signal transmission characteristics, reducing attenuation from typical coaxial cable values (e.g., 0.5-2 dB per 100 meters at RF frequencies) to fiber optic values (e.g., 0.2 dB per kilometer), enabling long-distance transmission with minimal energy loss.
3Adaptability or versatility
If phase measurements are performed over long distances, then remote device characteristics can be measured, but the phase information becomes unreliable due to signal path effects
Solution Approach 1:
The fiber optic cable acts as a dedicated intermediary channel for transmitting both the synchronization signal and the device under test signals. This separate, controlled transmission path isolates the measurement signals from external electromagnetic interference and environmental factors that would otherwise corrupt phase information, maintaining measurement reliability over long distances.
Solution Approach 2:
The replacement of coaxial cable with fiber optic cable eliminates the electromagnetic field interactions that cause phase shifts and signal degradation. The optical transmission medium is immune to electromagnetic interference, ground loops, and capacitive effects that plague electrical signal transmission, thereby preserving phase information integrity for remote measurements.
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 accurate phase synchronization over longer distances with reduced signal attenuation, allowing for precise measurement of electrical characteristics of devices under test, even in scenarios where traditional coaxial cables are impractical.
Implementation Method 1
A synchronization signal is transmitted from a measurement instrument to a receiver through a fiber optic cable
Implementation Method 2
A duplexer is configured to transmit a synchronization signal from the measurement instrument to the receiver via fiber optic cable and retransmit the received synchronization signal from the receiver to the measurement instrument
Data Source
AI summary
A measurement instrument for measuring electrical characteristics of a device under test (DUT) includes a synchronization signal generator, a coarse phase detection counter and a fine phase detection counter. The synchronization signal generator is connectable with a receiver via a fiber optic cable and a duplexer configured to transmit a synchronization signal from the measurement instrument to the receiver and retransmit the received synchronization signal from the receiver to the measurement instrument. The coarse phase detection counter and the fine phase detection counter are configured to determine one or both of a distance from the receiver to the measurement instrument and a phase shift in the synchronization signal between the receiver and the measurement instrument.