Frame synchronization: Difference between revisions

Revision as of 17:12, 22 November 2010

Revision as of 20:55, 22 November 2010

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== Framing ==

[[Image:Frame Synced Stream.jpg|framghjgj gjghj ghjghjgjgjg ghj'''ghj''''''Bold text'''''''''eframe|none|Frame Synchronized PCM Stream -- Telemetry Application]]

If the transmission is temporarily interrupted, or a [[bit slip]] event occurs, the receiver must re-synchronize.

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===Television===

A '''frame synchronizer''' is a device used in live [[television]] production to [[Timebase correction|match the timing]] of an incoming [[video]] source to the timing of an existing video system. They are often used to "time in" consumer [[video equipment]] to a professional system but can be used to stabilize any video. The frame synchronizer essentially takes a [[picture]] of each [[Film frame|frame]] of incoming video and then outputs it immediately with the correct [[synchronization]] signals to match an existing video system.

===Telemetry===

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The Frame Synchronizer immediately follows the Bit Synchronizer in most telemetry applications. Without frame synchronization [[Decommutator|decommutation]] is impossible.

[[Image:Frame Synced Stream.jpg|frame|none|Frame Synchronized PCM Stream]]

The Frame Sync Pattern is a known binary pattern which repeats at a regular interval within the PCM stream. The frame synchronizer recognizes this pattern and aligns the data into Minor Frames or Sub Frames. Typically the frame sync pattern is followed by a counter (Sub-Frame ID) which dictates which minor or sub frame in the series is being transmitted. This becomes increasingly important in the decommutation stage where all data is deciphered as to what attribute was sampled. Different commutations require a constant awareness of which section of the major frame is being decoded.