Ensemble Designs 9430 Flexible Matrix Router for 3G / HD / SD / ASI - Manual (Page 78)

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Avenue 9430 Flexible Matrix Router Installation, Configuration and Operations Guide
Switch Point Identification
As described in the section Setting Up Timing and Genlock on page 70, the video format and
horizontal and vertical timing for the Primary TSG determines timing and location of the switch point
in the vertical interval. Under SMPTE RP 168, the switch point varies from one format to another. In
general, it should occur during the middle portion of a specific line in the vertical interval. These
locations, which are as far away as possible from the SAV and EAV digital sync words, offer the best
opportunity to minimize the disturbance that is inevitably produced by switching between two digital
bit streams – even streams that are very closely timed to each other.
Note: This discussion of vertical interval switching applies ONLY to the switching that takes
place in the SDI matrix. Router outputs which are delivered through a 9435 Clean
Switch do not suffer from any disturbance when a switch takes place. This holds
true even when switching between un-timed or asynchronous sources. The 9435
Clean Switch is operating on deserialized (parallel) data where absolutely precise
alignment is possible. The switch takes place between these perfectly aligned signals
before being reserialized and sent to the output.
In order to help identify when and where the switch is taking place, the TSGs have a marking feature.
When the Switch Mark is enabled, a white pulse will be inserted on the switching line. The beginning
and ending of the pulse corresponds to the RP 168 specified switching area. This line can be viewed on
a digital waveform monitor, or on a picture monitor which offers V Delay.
Display of Y Channel for 1080i/59.94 with Switch Mark Enabled.