Video Signal Phase Synchronization Across Independent Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for synchronizing video signals across multiple networks using a grand master clock face challenges in maintaining synchronization due to independent time synchronization in each network, leading to phase mismatch issues and unsynchronized start times during image capturing.
Innovation Solution
An apparatus that generates and transmits synchronization format information and phase difference information for vertical and horizontal synchronizing frequencies, allowing video synchronizing signals to synchronize without adjusting the grand master clock time, enabling phase matching between signals across networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the time of grand master clock is adjusted in each network to synchronize video signals, then local synchronization within each network is improved, but the times of respective grand master clocks shift to each other, making synchronization across groups impossible
Solution Approach 1:
The patent segments the synchronization problem into two independent parts: time synchronization (handled by PTP grand master clock adjustment) and phase synchronization (handled by video synchronizing signal adjustment). This allows each network to independently adjust its grand master clock for local time synchronization without affecting other networks, while the phase synchronization is achieved through the video signal itself rather than through grand master clock coordination.
Solution Approach 2:
The patent introduces an intermediary approach where the video synchronizing signal itself serves as the reference for phase synchronization, rather than using the grand master clock as the sole reference. The phase difference detection unit measures phase differences based on the video synchronizing signal, and the adjustment unit corrects phase deviations independently of grand master clock time adjustments, allowing cross-group synchronization without requiring grand master clock times to be aligned.
2Loss of time
If reference image synchronizing data is used to generate operation synchronizing signals on the receiving side, then time synchronization is achieved, but the phases of the video synchronizing signals cannot be matched
Solution Approach 1:
The patent separates time synchronization and phase synchronization into distinct functional units. The time synchronization is handled by the PTP protocol and grand master clock adjustment, while the phase synchronization is handled by a separate phase difference detection unit that measures phase differences based on the video synchronizing signal and a phase adjustment unit that corrects phase deviations. This segmentation allows both time and phase synchronization to be optimized independently.
Solution Approach 2:
The patent implements a feedback mechanism where the phase difference detection unit continuously monitors the phase difference between the input video synchronizing signal and the output video synchronizing signal. Based on this feedback, the adjustment unit dynamically adjusts the phase of the output signal to maintain synchronization. This closed-loop feedback ensures that phase matching precision is maintained even when grand master clock times shift between networks.
3Measurement precision
If PTP video synchronization is used to synchronize video signals via IP network, then time synchronization in units of microsecond/nanosecond is achieved, but synchronization cannot be appropriately performed when a plurality of networks with independent time synchronization are present
Solution Approach 1:
The patent segments the synchronization function into time synchronization (handled by PTP at microsecond/nanosecond precision) and phase synchronization (handled by video signal analysis). This allows PTP to operate independently in each network with high time synchronization precision, while the phase synchronization layer operates above the PTP layer, detecting and correcting phase differences based on the actual video synchronizing signals. This segmentation enables multi-network synchronization capability because each network can independently manage its own time synchronization without requiring coordination of grand master clock times across networks.
Solution Approach 2:
The patent adds another dimension to the synchronization architecture by introducing phase synchronization as a separate layer above time synchronization. Instead of relying solely on time synchronization precision, the system measures and adjusts phase differences in the video signal domain. This dimensional addition allows the system to achieve synchronization across multiple networks with independent time synchronization, as the phase adjustment operates independently of the absolute time references used by PTP in each network.
Data Source
AI summary
An apparatus includes a generating unit and a transmitting unit. The generating unit generates synchronization format information regarding a vertical synchronizing frequency and a horizontal synchronizing frequency of a first video synchronizing signal, and generates phase difference information indicating a phase difference between the first video synchronizing signal and a first reference signal synchronized with a grand master clock. The transmitting unit transmits the synchronization format information and the phase difference information to an external apparatus that can generates a second video synchronizing signal synchronized with the first video synchronizing signal.