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ADV7188 lock time

Question asked by apomerants on Mar 24, 2015
Latest reply on Jul 9, 2015 by DerekBurke

Hello

We are facing a problem with the ADV7188 decoder lock time while switching (by using two "regular" op-amp and not a special video mux component) between two cameras (not synced between them) at the decoder input. In other systems where during self tests the video is disconnected for 1-2 seconds and then returned, we face in several systems same problem.

The problem is from time to time a long time (5-10sec) of the decoder to lock on the "new" input video stream, and if performing this "disconnect/ connect" sequence for several times, we can face sometimes even a period of up to 20 seconds of a black/ blinking screen.

We have noticed the above is much worse with PAL than in NTSC. Any logic with this?

 

I have raised this question few years ago and got from Analog a file with initialization sequence at a similar decoder that should improve the switching time. But this file was too "strange" to be implemented (accessing registers that are not on the datasheet etc.)

 

Can you please explain to me again the reason for the above?

Is there a way to improve the above at our current card, mainly in a two cameras scenario?

Is there another decoder that is known for better lock time performance?

 

Any idea/ direction of how to improve  the above situation will be appreciated,

(best if with minor HW changes...)

 

Thanks

 

Amnon

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