NEW FEATURES FOR AN EVEN SAFER SWITCH (September 2011)

Crystal Vision has added new features to its Safe Switch-L 3G, which provides clean and intelligent 2 x 2 switching between two 3Gb/s, HD or SD sources and is the only way to guarantee a clean switch. The two new features are processed frozen picture detection and sophisticated operation on loss of reference.

With Safe Switch-L 3G, the clean switching comes from the full framestore synchroniser on each input timed to an analogue reference, which means that it can correct for any timing difference between the two inputs resulting in no disruption to the output picture when a switch takes place.

Ideal for planned maintenance switches to manually re-route a good signal around broken equipment, it can also be used as an intelligent emergency transmission switch by engineers who do not want to restrict themselves to timed inputs, with the option of selecting from 16 different fault conditions to automatically trigger the switch.

These 16 parameters are input missing, input video standard incorrect, EDH missing, EDH full field error, EDH active picture error, line CRC error, audio group 1 missing, audio group 2 missing, audio group 3 missing, audio group 4 missing, active video black, active video frozen and audio silence on any channel in a selected group.

Safe Switch-L 3G will switch away from an error on the user-selected input only if the other input is free of that fault. If both inputs have different alarms, it will use the most significant alarm to decide which feed to select. Other features include relay bypass protection and 12 bi-directional GPIs for flexible GPI control and monitoring of alarm conditions.

The first new feature – processed frozen picture detection – is an extension of the active video frozen parameter, and was developed following a customer request. With some processes – such as video compression or converting to analogue and back – introducing small changes frame-to-frame even if the input picture is frozen, the processed frozen picture detection feature allows Safe Switch-L 3G to distinguish between this noise and real changes in the picture content – and so correctly flag up an error condition and auto switch.

The second new feature is sophisticated operation on loss of reference – an unusual and technically-advanced feature which further extends Safe Switch-L 3G’s primary purpose of protecting the output from any disruption. Safe Switch-L 3G will basically change its timing smoothly between the reference and the inputs, keeping the output valid at all times. In normal operation the output timing is derived from the reference. If the reference is lost, Safe Switch-L 3G uses an input as the basis for the output clock, changing to the same sample/line/frame rate as input 1 without disrupting the output video.  If the reference returns, the board adjusts its timing back to line up with the reference – again without disrupting the output signal.