Transmission Apparatus Leap Second Synchronization Control
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Solution Overview
Problem
Leap seconds, which occur once in several years, pose a challenge in presentation control for next-generation broadcasting systems using IP protocols like MMT, as they disrupt synchronization and can cause significant influence on reception quality.
Innovation Solution
A transmission apparatus that generates and transmits absolute time information synchronized with an external source, shifting the occurrence time of leap seconds to minimize their impact, and includes mode information to alert receivers, allowing them to prepare and adjust presentation times accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If absolute time information is used for presentation synchronization in next-generation broadcasting systems, then synchronization accuracy is improved, but leap seconds cause disruption to reception quality
Solution Approach 1:
The transmission apparatus performs preliminary action by generating mode information in advance that indicates the occurrence time of leap seconds. This allows reception apparatus to prepare ahead of time by adjusting their presentation time control, thereby maintaining reception quality despite the synchronization disruption caused by leap seconds in the absolute time information.
Solution Approach 2:
Mode information acts as an intermediary between the absolute time information and the presentation time control. It carries leap second occurrence time information separately, enabling the reception apparatus to distinguish between normal time progression and leap second events, thus preventing direct disruption to playback while maintaining synchronization accuracy.
2Reliability
If leap second occurrence time is shifted to minimize disruption, then reception quality is improved, but time information accuracy may be compromised
Solution Approach 1:
Mode information serves as an intermediary that preserves the relationship between shifted leap second occurrence time and actual absolute time. By encoding the original occurrence time in mode information, the system maintains time information accuracy for synchronization purposes while allowing the leap second to be handled at a different time to improve reception quality.
Solution Approach 2:
The system performs preliminary action by calculating and transmitting mode information that indicates the shifted leap second occurrence time in advance. This allows the reception apparatus to adjust presentation times proactively, maintaining both reception quality and time accuracy through coordinated time management.
Data Source
AI summary
A time information generating unit generates absolute time information synchronized with absolute time information acquired from an external source. The time information generating unit generates time information by shifting, to shifted time, occurrence time of a leap second that can be represented by the absolute time information acquired from the external source. A transmission unit transmits a signal including transmission media and the absolute time information generated by the time information generating unit. Thereby, influence on a reception side by occurrence of a leap second is suppressed.